buble - npm Package Compare versions

Comparing version 0.4.5 to 0.4.6

CHANGELOG.md

 # buble changelog
 
+## 0.4.6
+
+* Report locations of parse/compile errors ([#4](https://gitlab.com/Rich-Harris/buble/issues/4))
+
 ## 0.4.5
@@ -4,0 +8,0 @@

dist/buble.es.js

 import { parse } from 'acorn';
 import MagicString from 'magic-string';
-import { walk } from 'estree-walker';
+import 'estree-walker';
 
@@ -46,12 +46,2 @@ var statementsWithBlocks = {
 
-Node.prototype.findChildren = function findChildren ( type ) {
-	var children = [];
-	walk( this, {
-		enter: function ( node ) {
-			if ( node.type === type ) children.push( node );
-		}
-	});
-	return children;
-};
-
 Node.prototype.findLexicalBoundary = function findLexicalBoundary () {
@@ -62,3 +52,3 @@ return this.parent.findLexicalBoundary();
 Node.prototype.findNearest = function findNearest ( type ) {
-	if ( typeof type === 'string' ) type = new RegExp( "^" + type + "$" );
+	if ( typeof type === 'string' ) type = new RegExp( ("^" + type + "$") );
 	if ( type.test( this.type ) ) return this;
@@ -84,3 +74,3 @@ return this.parent.findNearest( type );
 		if ( Array.isArray( value ) ) {
-			value.forEach( function ( node ) { return node.initialise(); } );
+			value.forEach( function ( node ) { return node && node.initialise(); } );
 		} else if ( value && typeof value === 'object' ) {
@@ -103,3 +93,3 @@ value.initialise();
 		if ( Array.isArray( value ) ) {
-			value.forEach( function ( node ) { return node.transpile( code ); } );
+			value.forEach( function ( node ) { return node && node.transpile( code ); } );
 		} else if ( value && typeof value === 'object' ) {
@@ -111,2 +101,78 @@ value.transpile( code );
 
+function locate ( source, index ) {
+	var lines = source.split( '\n' );
+	var len = lines.length;
+
+	var lineStart = 0;
+	var i;
+
+	for ( i = 0; i < len; i += 1 ) {
+		var line = lines[i];
+		var lineEnd =  lineStart + line.length + 1; // +1 for newline
+
+		if ( lineEnd > index ) {
+			return { line: i + 1, column: index - lineStart, char: i };
+		}
+
+		lineStart = lineEnd;
+	}
+
+	throw new Error( 'Could not determine location of character' );
+}
+
+function pad ( num, len ) {
+	var result = String( num );
+	return result + repeat( ' ', len - result.length );
+}
+
+function repeat ( str, times ) {
+	var result = '';
+	while ( times-- ) result += str;
+	return result;
+}
+
+function getSnippet ( source, loc, length ) {
+	if ( length === void 0 ) length = 1;
+
+	var first = Math.max( loc.line - 5, 0 );
+	var last = loc.line;
+
+	var numDigits = String( last ).length;
+
+	var lines = source.split( '\n' ).slice( first, last );
+
+	var lastLine = lines[ lines.length - 1 ];
+	var offset = lastLine.slice( 0, loc.column ).replace( /\t/g, '  ' ).length;
+
+	var snippet = lines
+		.map( function ( line, i ) { return ("" + (pad( i + first + 1, numDigits )) + " : " + (line.replace( /\t/g, '  '))); } )
+		.join( '\n' );
+
+	snippet += '\n' + repeat( ' ', numDigits + 3 + offset ) + repeat( '^', length );
+
+	return snippet;
+}
+
+var CompileError = (function (Error) {
+	function CompileError ( node, message ) {
+		Error.call(this);
+
+		var source = node.program.magicString.original;
+		var loc = locate( source, node.start );
+
+		this.name = 'CompileError';
+		this.message = message + " (" + (loc.line) + ":" + (loc.column) + ")";
+
+		this.stack = new Error().stack.replace( new RegExp( (".+new " + (this.name) + ".+\\n"), 'm' ), '' );
+
+		this.loc = loc;
+		this.snippet = getSnippet( source, loc, node.end - node.start );
+	}
+
+	CompileError.prototype = Object.create( Error && Error.prototype );
+	CompileError.prototype.constructor = CompileError;
+
+	return CompileError;
+}(Error));
+
 var AssignmentExpression = (function (Node) {
@@ -124,4 +190,3 @@ function AssignmentExpression () {
 			if ( declaration && declaration.kind === 'const' ) {
-				// TODO location etc
-				throw new Error( "" + (this.left.name) + " is read-only" );
+				throw new CompileError( this.left, ("" + (this.left.name) + " is read-only") );
 			}
@@ -210,5 +275,5 @@ }
 				if ( nextMethod ) {
-					code.insert( nextMethod.start, "\n\n" + indentation + "" );
+					code.insert( nextMethod.start, ("\n\n" + indentation) );
 				} else {
-					code.insert( constructor.end, "\n\n" + indentation + "" );
+					code.insert( constructor.end, ("\n\n" + indentation) );
 				}
@@ -218,4 +283,4 @@ }
 			var fn = "function " + name + " () {" + ( superName ?
-				"\n" + indentation + "" + indentStr + "" + superName + ".apply(this, arguments);\n" + indentation + "}" :
-				"}" ) + ( inFunctionExpression ? '' : ';' ) + ( this.body.length ? "\n\n" + indentation + "" : '' );
+				("\n" + indentation + "" + indentStr + "" + superName + ".apply(this, arguments);\n" + indentation + "}") :
+				("}") ) + ( inFunctionExpression ? '' : ';' ) + ( this.body.length ? ("\n\n" + indentation) : '' );
 			code.insert( this.start, fn );
@@ -228,5 +293,5 @@ }
 			if ( constructor ) {
-				code.insert( constructor.end, "\n\n" + indentation + "" + inheritanceBlock );
+				code.insert( constructor.end, "\n\n" + indentation + inheritanceBlock );
 			} else {
-				code.insert( this.start, inheritanceBlock + "\n\n" + indentation + "" );
+				code.insert( this.start, inheritanceBlock + "\n\n" + indentation );
 			}
@@ -237,3 +302,3 @@ }
 			if ( method.kind === 'constructor' ) {
-				code.overwrite( method.key.start, method.key.end, "function " + name + "" );
+				code.overwrite( method.key.start, method.key.end, ("function " + name) );
 				return;
@@ -245,6 +310,6 @@ }
 			var lhs = method.static ?
-				"" + name + "." + (method.key.name) + "" :
-				"" + name + ".prototype." + (method.key.name) + "";
+				("" + name + "." + (method.key.name)) :
+				("" + name + ".prototype." + (method.key.name));
 
-			code.insert( method.start, "" + lhs + " = function " );
+			code.insert( method.start, ("" + lhs + " = function ") );
 			code.insert( method.end, ';' );
@@ -276,9 +341,2 @@
 
-	var isExcluded = {};
-	node.findChildren( 'TemplateLiteral' ).forEach( function ( node ) {
-		for ( var i = node.start; i < node.end; i += 1 ) {
-			isExcluded[i] = true;
-		}
-	});
-
 	if ( code.original.slice( start - indentStr.length, start ) === indentStr ) {
@@ -291,3 +349,3 @@ code.remove( start - indentStr.length, start );
 	while ( match = pattern.exec( slice ) ) {
-		if ( !isExcluded[ match.index ] ) code.remove( start + match.index, start + match.index + indentStr.length );
+		if ( !node.program.indentExclusions[ match.index ] ) code.remove( start + match.index, start + match.index + indentStr.length );
 	}
@@ -318,8 +376,8 @@ }
 		var intro = this.superClass ?
-			"var " + (this.name) + " = (function (" + superName + ") {\n" + indentation + "" + indentStr + "" :
-			"var " + (this.name) + " = ";
+			("var " + (this.name) + " = (function (" + superName + ") {\n" + indentation + "" + indentStr) :
+			("var " + (this.name) + " = ");
 
 		var outro = this.superClass ?
-			"\n\n" + indentation + "" + indentStr + "return " + (this.name) + ";\n" + indentation + "}(" + superName + "));" :
-			"";
+			("\n\n" + indentation + "" + indentStr + "return " + (this.name) + ";\n" + indentation + "}(" + superName + "));") :
+			("");
 
@@ -359,7 +417,7 @@ code.remove( this.start, this.body.start );
 
-		code.overwrite( this.start, this.body.start, "(function (" + (superName || '') + ") {\n" + indentation + "" + indentStr + "" );
+		code.overwrite( this.start, this.body.start, ("(function (" + (superName || '') + ") {\n" + indentation + "" + indentStr) );
 
 		this.body.transpile( code, true );
 
-		code.insert( this.end, "\n\n" + indentation + "" + indentStr + "return " + (this.name) + ";\n" + indentation + "}(" + (superName || '') + "))" );
+		code.insert( this.end, ("\n\n" + indentation + "" + indentStr + "return " + (this.name) + ";\n" + indentation + "}(" + (superName || '') + "))") );
 	};
@@ -382,5 +440,5 @@
 		if ( this.declaration.type === 'ClassDeclaration' ) {
-			code.insert( this.end, "\n\n" + (this.getIndentation()) + "" );
+			code.insert( this.end, ("\n\n" + (this.getIndentation())) );
 			code.move( this.start, this.declaration.start, this.end );
-			code.insert( this.end, "" + (this.declaration.id.name) + ";" );
+			code.insert( this.end, ("" + (this.declaration.id.name) + ";") );
 		}
@@ -476,4 +534,4 @@ };
 
-			var before = "var forLoop = function ( " + (names$1.join( ', ' )) + " ) " + ( this.body.synthetic ? "{\n" + indentation + "" + (code.getIndentString()) + "" : '' );
-			var after = ( this.body.synthetic ? "\n" + indentation + "}" : '' ) + ";\n\n" + indentation + "";
+			var before = "var forLoop = function ( " + (names$1.join( ', ' )) + " ) " + ( this.body.synthetic ? ("{\n" + indentation + "" + (code.getIndentString())) : '' );
+			var after = ( this.body.synthetic ? ("\n" + indentation + "}") : '' ) + ";\n\n" + indentation;
 
@@ -484,3 +542,3 @@ code.insert( this.start, before );
 
-			code.insert( this.end, "forLoop( " + (names$1.join( ', ' )) + " );" );
+			code.insert( this.end, ("forLoop( " + (names$1.join( ', ' )) + " );") );
 		}
@@ -658,7 +716,2 @@
 
-function unsupported ( node, description ) {
-	// TODO show offending snippet
-	throw new Error( "" + description + ". See TK for more information" );
-}
-
 var Property = (function (Node) {
@@ -674,3 +727,3 @@ function Property () {
 		if ( this.computed ) {
-			unsupported( this, 'Computed properties are not supported' );
+			throw new CompileError( this.key, 'Computed properties are not supported' );
 		}
@@ -684,5 +737,5 @@
 			if ( this.shorthand ) {
-				code.insert( this.start, "" + (this.key.name) + ": " );
+				code.insert( this.start, ("" + (this.key.name) + ": ") );
 			} else if ( this.method ) {
-				code.insert( this.key.end, ": function" );
+				code.insert( this.key.end, (": function") );
 			}
@@ -707,14 +760,13 @@ }
 		this.method = this.findNearest( 'MethodDefinition' );
-		this.superClassName = this.findNearest( 'ClassBody' ).parent.superClass.name;
+		if ( !this.method ) throw new CompileError( this, 'use of super outside class method' );
 
-		if ( !this.method ) {
-			throw new Error( 'super outside method' ); // TODO location etc
-		}
+		var parentClass = this.findNearest( 'ClassBody' ).parent;
+		this.superClassName = parentClass.superClass && parentClass.superClass.name;
 
-		this.isCalled = this.parent.type === 'CallExpression';
+		if ( !this.superClassName ) throw new CompileError( this, 'super used in base class' );
 
-		if ( this.method.kind === 'constructor' ) {
-			if ( !this.isCalled ) throw new Error( 'super cannot be referred to in constructor outside a call expression' ); // TODO this is cryptic
-		} else {
-			if ( this.isCalled ) throw new Error( 'super() not allowed outside class constructor' );
+		this.isCalled = this.parent.type === 'CallExpression' && this === this.parent.callee;
+
+		if ( this.method.kind !== 'constructor' && this.isCalled ) {
+			throw new CompileError( this, 'super() not allowed outside class constructor' );
 		}
@@ -725,3 +777,3 @@
 		if ( !this.isCalled && !this.isMember ) {
-			throw new Error( 'Unexpected use of `super` (expected `super(...)` or `super.*`)' );
+			throw new CompileError( this, 'Unexpected use of `super` (expected `super(...)` or `super.*`)' );
 		}
@@ -731,3 +783,3 @@ };
 	Super.prototype.transpile = function transpile ( code ) {
-		var expression = this.isCalled ? this.superClassName : "" + (this.superClassName) + ".prototype";
+		var expression = this.isCalled ? this.superClassName : ("" + (this.superClassName) + ".prototype");
 		code.overwrite( this.start, this.end, expression, true );
@@ -741,5 +793,5 @@
 			if ( callExpression.arguments.length ) {
-				code.insert( callExpression.arguments[0].start, "this, " );
+				code.insert( callExpression.arguments[0].start, ("this, ") );
 			} else {
-				code.insert( callExpression.end - 1, "this" );
+				code.insert( callExpression.end - 1, ("this") );
 			}
@@ -761,3 +813,3 @@ }
 	TaggedTemplateExpression.prototype.initialise = function initialise () {
-		unsupported( this, 'Tagged template expressions are not supported' );
+		throw new CompileError( this.tag, 'Tagged template expressions are not supported' );
 	};
@@ -768,2 +820,17 @@
 
+var TemplateElement = (function (Node) {
+	function TemplateElement () {
+		Node.apply(this, arguments);
+	}
+
+	TemplateElement.prototype = Object.create( Node && Node.prototype );
+	TemplateElement.prototype.constructor = TemplateElement;
+
+	TemplateElement.prototype.initialise = function initialise () {
+		this.program.templateElements.push( this );
+	};
+
+	return TemplateElement;
+}(Node));
+
 var TemplateLiteral = (function (Node) {
@@ -795,3 +862,3 @@ function TemplateLiteral () {
 				var stringified = JSON.stringify( node.value.cooked );
-				var replacement = ( closeParenthesis ? ')' : '' ) + ( ( node.tail && !node.value.cooked.length && i !== 0 ) ? '' : "" + (i ? ' + ' : '') + "" + stringified + "" );
+				var replacement = ( closeParenthesis ? ')' : '' ) + ( ( node.tail && !node.value.cooked.length && i !== 0 ) ? '' : ("" + (i ? ' + ' : '') + "" + stringified) );
 				code.overwrite( lastIndex, node.end, replacement );
@@ -859,4 +926,3 @@
 			if ( declaration && declaration.kind === 'const' ) {
-				// TODO location etc
-				throw new Error( "" + (this.argument.name) + " is read-only" );
+				throw new CompileError( this, ("" + (this.argument.name) + " is read-only") );
 			}
@@ -911,4 +977,4 @@ }
 			this.id[ this.isObjectPattern ? 'properties' : 'elements' ].forEach( function ( node ) {
-				if ( /Pattern/.test( this$1.isObjectPattern ? node.value.type : node.type ) ) {
-					unsupported( this$1, 'Compound destructuring is not supported' );
+				if ( node && /Pattern/.test( this$1.isObjectPattern ? node.value.type : node.type ) ) {
+					throw new CompileError( node.value, 'Compound destructuring is not supported' );
 				}
@@ -923,2 +989,4 @@ });
 	VariableDeclarator.prototype.transpile = function transpile ( code ) {
+		var this$1 = this;
+
 		if ( this.id.type !== 'Identifier' ) {
@@ -929,5 +997,5 @@ var simple = this.init.type === 'Identifier';
 			if ( !simple ) {
-				code.insert( this.start, "" + name + " = " );
+				code.insert( this.start, ("" + name + " = ") );
 				code.move( this.init.start, this.init.end, this.start );
-				code.insert( this.start, ", " );
+				code.insert( this.start, (", ") );
 			} else {
@@ -941,11 +1009,17 @@ code.remove( this.init.start, this.init.end );
 
-			props.forEach( this.isObjectPattern ?
-				function ( property ) {
-					code.overwrite( property.start, property.end, "" + (property.value.name) + " = " + name + "." + (property.key.name) + "" );
-				} :
-				function ( property, i ) {
-					code.overwrite( property.start, property.end, "" + (property.name) + " = " + name + "[" + i + "]" );
-				});
+			var lastIndex = this.start;
+			var first = true;
 
-			code.remove( props[ props.length - 1 ].end, this.init.start );
+			props.forEach( function ( property, i ) {
+				if ( property ) {
+					var lhs = this$1.isObjectPattern ? property.value.name : property.name;
+					var rhs = this$1.isObjectPattern ? ("" + name + "." + (property.key.name)) : ("" + name + "[" + i + "]");
+
+					code.overwrite( lastIndex, property.end, ("" + (first ? '' : ', ') + "" + lhs + " = " + rhs) );
+					lastIndex = property.end;
+					first = false;
+				}
+			});
+
+			code.remove( lastIndex, this.init.start );
 		}
@@ -976,2 +1050,3 @@
 	TaggedTemplateExpression: TaggedTemplateExpression,
+	TemplateElement: TemplateElement,
 	TemplateLiteral: TemplateLiteral,
@@ -1025,4 +1100,3 @@ ThisExpression: ThisExpression,
 			if ( this$1.declarations[ name ] ) {
-				// TODO add location for debugging...
-				throw new Error( "" + name + " is already declared" );
+				throw new CompileError( node, ("" + name + " is already declared") );
 			}
@@ -1060,3 +1134,3 @@
 		while ( this.declarations[ name ] || this.references[ name ] || this.aliases[ name ] || name in reserved ) {
-			name = "" + base + "$" + (counter++) + "";
+			name = "" + base + "$" + (counter++);
 		}
@@ -1157,3 +1231,3 @@
 		if ( this.thisAlias ) {
-			if ( addedStuff ) code.insert( start, "\n" + indentation + "" );
+			if ( addedStuff ) code.insert( start, ("\n" + indentation) );
 			var assignment$1 = "var " + (this.thisAlias) + " = this;";
@@ -1169,9 +1243,9 @@ code.insert( start, assignment$1 );
 			params.filter( function ( param ) { return param.type === 'AssignmentPattern'; } ).forEach( function ( param ) {
-				if ( addedStuff ) code.insert( start, "\n" + indentation + "" );
+				if ( addedStuff ) code.insert( start, ("\n" + indentation) );
 
-				var lhs = "if ( " + (param.left.name) + " === void 0 ) " + (param.left.name) + "";
+				var lhs = "if ( " + (param.left.name) + " === void 0 ) " + (param.left.name);
 				code
-					.insert( start, "" + lhs + "" )
+					.insert( start, ("" + lhs) )
 					.move( param.left.end, param.right.end, start )
-					.insert( start, ";" );
+					.insert( start, (";") );
 
@@ -1191,3 +1265,3 @@ addedStuff = true;
 
-					if ( addedStuff ) code.insert( start, "\n" + indentation + "" );
+					if ( addedStuff ) code.insert( start, ("\n" + indentation) );
 
@@ -1201,3 +1275,3 @@ var key = prop.key.name;
 						var value = prop.value.name;
-						code.insert( start, "var " + value + " = " + ref + "." + key + ";" );
+						code.insert( start, ("var " + value + " = " + ref + "." + key + ";") );
 					} else if ( prop.value.type === 'AssignmentPattern' ) {
@@ -1209,9 +1283,9 @@ code.remove( prop.value.start, prop.value.right.start );
 						code
-							.insert( start, "var " + ref + "_" + key + " = ref." + key + ", " + value$1 + " = ref_" + key + " === void 0 ? " )
+							.insert( start, ("var " + ref + "_" + key + " = ref." + key + ", " + value$1 + " = ref_" + key + " === void 0 ? ") )
 							.move( prop.value.right.start, prop.value.right.end, start )
-							.insert( start, " : ref_" + key + ";" );
+							.insert( start, (" : ref_" + key + ";") );
 					}
 
 					else {
-						throw new Error( "" + (prop.type) + " not currently supported" ); // TODO...
+						throw new CompileError( prop, ("Compound destructuring is not supported") );
 					}
@@ -1236,3 +1310,3 @@
 
-					if ( addedStuff ) code.insert( start, "\n" + indentation + "" );
+					if ( addedStuff ) code.insert( start, ("\n" + indentation) );
 
@@ -1243,3 +1317,3 @@ if ( element.type === 'Identifier' ) {
 
-						code.insert( start, "var " + (element.name) + " = " + ref + "[" + i + "];" );
+						code.insert( start, ("var " + (element.name) + " = " + ref + "[" + i + "];") );
 					} else if ( element.type === 'AssignmentPattern' ) {
@@ -1251,9 +1325,9 @@ code.remove( element.start, element.right.start );
 						code
-							.insert( start, "var " + ref + "_" + i + " = ref[" + i + "], " + name + " = ref_" + i + " === void 0 ? " )
+							.insert( start, ("var " + ref + "_" + i + " = ref[" + i + "], " + name + " = ref_" + i + " === void 0 ? ") )
 							.move( element.right.start, element.right.end, start )
-							.insert( start, " : ref_" + i + ";" );
+							.insert( start, (" : ref_" + i + ";") );
 					}
 
 					else {
-						throw new Error( "" + (element.type) + " not currently supported" ); // TODO...
+						throw new CompileError( element, ("Compound destructuring is not supported") );
 					}
@@ -1280,3 +1354,3 @@
 
-				if ( addedStuff ) code.insert( start, "\n" + indentation + "" );
+				if ( addedStuff ) code.insert( start, ("\n" + indentation) );
 
@@ -1288,5 +1362,5 @@ var name = lastParam.argument.name;
 				if ( count ) {
-					code.insert( start, "var " + name + " = [], " + len + " = arguments.length - " + count + ";\n" + indentation + "while ( " + len + "-- > 0 ) " + name + "[ " + len + " ] = arguments[ " + len + " + " + count + " ];" );
+					code.insert( start, ("var " + name + " = [], " + len + " = arguments.length - " + count + ";\n" + indentation + "while ( " + len + "-- > 0 ) " + name + "[ " + len + " ] = arguments[ " + len + " + " + count + " ];") );
 				} else {
-					code.insert( start, "var " + name + " = [], " + len + " = arguments.length;\n" + indentation + "while ( " + len + "-- ) " + name + "[ " + len + " ] = arguments[ " + len + " ];" );
+					code.insert( start, ("var " + name + " = [], " + len + " = arguments.length;\n" + indentation + "while ( " + len + "-- ) " + name + "[ " + len + " ] = arguments[ " + len + " ];") );
 				}
@@ -1299,3 +1373,3 @@
 		if ( addedStuff ) {
-			code.insert( start, "\n\n" + indentation + "" );
+			code.insert( start, ("\n\n" + indentation) );
 		}
@@ -1307,3 +1381,3 @@
 
-				for ( var i = 0; i < declarations.length; i += 1 ) {
+				var forLoop = function ( i ) {
 					var declaration = declarations[i];
@@ -1317,3 +1391,5 @@ var alias = this$1.scope.createIdentifier( name );
 					}
-				}
+				};
+
+				for ( var i = 0; i < declarations.length; i += 1 ) forLoop( i );
 			});
@@ -1329,2 +1405,4 @@ }
 function Program ( source, ast ) {
+	var this$1 = this;
+
 	this.type = 'Root';
@@ -1340,3 +1418,12 @@
 
+	this.templateElements = [];
 	this.body.initialise();
+
+	this.indentExclusions = {};
+	this.templateElements.forEach( function ( node ) {
+		for ( var i = node.start; i < node.end; i += 1 ) {
+			this$1.indentExclusions[ node.start + i ] = true;
+		}
+	});
+
 	this.body.transpile( this.magicString );
@@ -1369,11 +1456,16 @@ }
 function transform ( source, options ) {
-	var ast = parse( source, {
-		ecmaVersion: 6,
-		preserveParens: true,
-		sourceType: 'module'
-	});
+	var ast;
 
-	var program = new Program( source, ast );
+	try {
+		ast = parse( source, {
+			ecmaVersion: 6,
+			preserveParens: true,
+			sourceType: 'module'
+		});
+	} catch ( err ) {
+		err.snippet = getSnippet( source, err.loc );
+		throw err;
+	}
 
-	return program.export( options );
+	return new Program( source, ast ).export( options );
 }
@@ -1380,0 +1472,0 @@

dist/buble.umd.js

@@ -50,12 +50,2 @@ (function (global, factory) {
 
-	Node.prototype.findChildren = function findChildren ( type ) {
-		var children = [];
-		estreeWalker.walk( this, {
-			enter: function ( node ) {
-				if ( node.type === type ) children.push( node );
-			}
-		});
-		return children;
-	};
-
 	Node.prototype.findLexicalBoundary = function findLexicalBoundary () {
@@ -66,3 +56,3 @@ return this.parent.findLexicalBoundary();
 	Node.prototype.findNearest = function findNearest ( type ) {
-		if ( typeof type === 'string' ) type = new RegExp( "^" + type + "$" );
+		if ( typeof type === 'string' ) type = new RegExp( ("^" + type + "$") );
 		if ( type.test( this.type ) ) return this;
@@ -88,3 +78,3 @@ return this.parent.findNearest( type );
 			if ( Array.isArray( value ) ) {
-				value.forEach( function ( node ) { return node.initialise(); } );
+				value.forEach( function ( node ) { return node && node.initialise(); } );
 			} else if ( value && typeof value === 'object' ) {
@@ -107,3 +97,3 @@ value.initialise();
 			if ( Array.isArray( value ) ) {
-				value.forEach( function ( node ) { return node.transpile( code ); } );
+				value.forEach( function ( node ) { return node && node.transpile( code ); } );
 			} else if ( value && typeof value === 'object' ) {
@@ -115,2 +105,78 @@ value.transpile( code );
 
+	function locate ( source, index ) {
+		var lines = source.split( '\n' );
+		var len = lines.length;
+
+		var lineStart = 0;
+		var i;
+
+		for ( i = 0; i < len; i += 1 ) {
+			var line = lines[i];
+			var lineEnd =  lineStart + line.length + 1; // +1 for newline
+
+			if ( lineEnd > index ) {
+				return { line: i + 1, column: index - lineStart, char: i };
+			}
+
+			lineStart = lineEnd;
+		}
+
+		throw new Error( 'Could not determine location of character' );
+	}
+
+	function pad ( num, len ) {
+		var result = String( num );
+		return result + repeat( ' ', len - result.length );
+	}
+
+	function repeat ( str, times ) {
+		var result = '';
+		while ( times-- ) result += str;
+		return result;
+	}
+
+	function getSnippet ( source, loc, length ) {
+		if ( length === void 0 ) length = 1;
+
+		var first = Math.max( loc.line - 5, 0 );
+		var last = loc.line;
+
+		var numDigits = String( last ).length;
+
+		var lines = source.split( '\n' ).slice( first, last );
+
+		var lastLine = lines[ lines.length - 1 ];
+		var offset = lastLine.slice( 0, loc.column ).replace( /\t/g, '  ' ).length;
+
+		var snippet = lines
+			.map( function ( line, i ) { return ("" + (pad( i + first + 1, numDigits )) + " : " + (line.replace( /\t/g, '  '))); } )
+			.join( '\n' );
+
+		snippet += '\n' + repeat( ' ', numDigits + 3 + offset ) + repeat( '^', length );
+
+		return snippet;
+	}
+
+	var CompileError = (function (Error) {
+		function CompileError ( node, message ) {
+			Error.call(this);
+
+			var source = node.program.magicString.original;
+			var loc = locate( source, node.start );
+
+			this.name = 'CompileError';
+			this.message = message + " (" + (loc.line) + ":" + (loc.column) + ")";
+
+			this.stack = new Error().stack.replace( new RegExp( (".+new " + (this.name) + ".+\\n"), 'm' ), '' );
+
+			this.loc = loc;
+			this.snippet = getSnippet( source, loc, node.end - node.start );
+		}
+
+		CompileError.prototype = Object.create( Error && Error.prototype );
+		CompileError.prototype.constructor = CompileError;
+
+		return CompileError;
+	}(Error));
+
 	var AssignmentExpression = (function (Node) {
@@ -128,4 +194,3 @@ function AssignmentExpression () {
 				if ( declaration && declaration.kind === 'const' ) {
-					// TODO location etc
-					throw new Error( "" + (this.left.name) + " is read-only" );
+					throw new CompileError( this.left, ("" + (this.left.name) + " is read-only") );
 				}
@@ -214,5 +279,5 @@ }
 					if ( nextMethod ) {
-						code.insert( nextMethod.start, "\n\n" + indentation + "" );
+						code.insert( nextMethod.start, ("\n\n" + indentation) );
 					} else {
-						code.insert( constructor.end, "\n\n" + indentation + "" );
+						code.insert( constructor.end, ("\n\n" + indentation) );
 					}
@@ -222,4 +287,4 @@ }
 				var fn = "function " + name + " () {" + ( superName ?
-					"\n" + indentation + "" + indentStr + "" + superName + ".apply(this, arguments);\n" + indentation + "}" :
-					"}" ) + ( inFunctionExpression ? '' : ';' ) + ( this.body.length ? "\n\n" + indentation + "" : '' );
+					("\n" + indentation + "" + indentStr + "" + superName + ".apply(this, arguments);\n" + indentation + "}") :
+					("}") ) + ( inFunctionExpression ? '' : ';' ) + ( this.body.length ? ("\n\n" + indentation) : '' );
 				code.insert( this.start, fn );
@@ -232,5 +297,5 @@ }
 				if ( constructor ) {
-					code.insert( constructor.end, "\n\n" + indentation + "" + inheritanceBlock );
+					code.insert( constructor.end, "\n\n" + indentation + inheritanceBlock );
 				} else {
-					code.insert( this.start, inheritanceBlock + "\n\n" + indentation + "" );
+					code.insert( this.start, inheritanceBlock + "\n\n" + indentation );
 				}
@@ -241,3 +306,3 @@ }
 				if ( method.kind === 'constructor' ) {
-					code.overwrite( method.key.start, method.key.end, "function " + name + "" );
+					code.overwrite( method.key.start, method.key.end, ("function " + name) );
 					return;
@@ -249,6 +314,6 @@ }
 				var lhs = method.static ?
-					"" + name + "." + (method.key.name) + "" :
-					"" + name + ".prototype." + (method.key.name) + "";
+					("" + name + "." + (method.key.name)) :
+					("" + name + ".prototype." + (method.key.name));
 
-				code.insert( method.start, "" + lhs + " = function " );
+				code.insert( method.start, ("" + lhs + " = function ") );
 				code.insert( method.end, ';' );
@@ -280,9 +345,2 @@
 
-		var isExcluded = {};
-		node.findChildren( 'TemplateLiteral' ).forEach( function ( node ) {
-			for ( var i = node.start; i < node.end; i += 1 ) {
-				isExcluded[i] = true;
-			}
-		});
-
 		if ( code.original.slice( start - indentStr.length, start ) === indentStr ) {
@@ -295,3 +353,3 @@ code.remove( start - indentStr.length, start );
 		while ( match = pattern.exec( slice ) ) {
-			if ( !isExcluded[ match.index ] ) code.remove( start + match.index, start + match.index + indentStr.length );
+			if ( !node.program.indentExclusions[ match.index ] ) code.remove( start + match.index, start + match.index + indentStr.length );
 		}
@@ -322,8 +380,8 @@ }
 			var intro = this.superClass ?
-				"var " + (this.name) + " = (function (" + superName + ") {\n" + indentation + "" + indentStr + "" :
-				"var " + (this.name) + " = ";
+				("var " + (this.name) + " = (function (" + superName + ") {\n" + indentation + "" + indentStr) :
+				("var " + (this.name) + " = ");
 
 			var outro = this.superClass ?
-				"\n\n" + indentation + "" + indentStr + "return " + (this.name) + ";\n" + indentation + "}(" + superName + "));" :
-				"";
+				("\n\n" + indentation + "" + indentStr + "return " + (this.name) + ";\n" + indentation + "}(" + superName + "));") :
+				("");
 
@@ -363,7 +421,7 @@ code.remove( this.start, this.body.start );
 
-			code.overwrite( this.start, this.body.start, "(function (" + (superName || '') + ") {\n" + indentation + "" + indentStr + "" );
+			code.overwrite( this.start, this.body.start, ("(function (" + (superName || '') + ") {\n" + indentation + "" + indentStr) );
 
 			this.body.transpile( code, true );
 
-			code.insert( this.end, "\n\n" + indentation + "" + indentStr + "return " + (this.name) + ";\n" + indentation + "}(" + (superName || '') + "))" );
+			code.insert( this.end, ("\n\n" + indentation + "" + indentStr + "return " + (this.name) + ";\n" + indentation + "}(" + (superName || '') + "))") );
 		};
@@ -386,5 +444,5 @@
 			if ( this.declaration.type === 'ClassDeclaration' ) {
-				code.insert( this.end, "\n\n" + (this.getIndentation()) + "" );
+				code.insert( this.end, ("\n\n" + (this.getIndentation())) );
 				code.move( this.start, this.declaration.start, this.end );
-				code.insert( this.end, "" + (this.declaration.id.name) + ";" );
+				code.insert( this.end, ("" + (this.declaration.id.name) + ";") );
 			}
@@ -480,4 +538,4 @@ };
 
-				var before = "var forLoop = function ( " + (names$1.join( ', ' )) + " ) " + ( this.body.synthetic ? "{\n" + indentation + "" + (code.getIndentString()) + "" : '' );
-				var after = ( this.body.synthetic ? "\n" + indentation + "}" : '' ) + ";\n\n" + indentation + "";
+				var before = "var forLoop = function ( " + (names$1.join( ', ' )) + " ) " + ( this.body.synthetic ? ("{\n" + indentation + "" + (code.getIndentString())) : '' );
+				var after = ( this.body.synthetic ? ("\n" + indentation + "}") : '' ) + ";\n\n" + indentation;
 
@@ -488,3 +546,3 @@ code.insert( this.start, before );
 
-				code.insert( this.end, "forLoop( " + (names$1.join( ', ' )) + " );" );
+				code.insert( this.end, ("forLoop( " + (names$1.join( ', ' )) + " );") );
 			}
@@ -662,7 +720,2 @@
 
-	function unsupported ( node, description ) {
-		// TODO show offending snippet
-		throw new Error( "" + description + ". See TK for more information" );
-	}
-
 	var Property = (function (Node) {
@@ -678,3 +731,3 @@ function Property () {
 			if ( this.computed ) {
-				unsupported( this, 'Computed properties are not supported' );
+				throw new CompileError( this.key, 'Computed properties are not supported' );
 			}
@@ -688,5 +741,5 @@
 				if ( this.shorthand ) {
-					code.insert( this.start, "" + (this.key.name) + ": " );
+					code.insert( this.start, ("" + (this.key.name) + ": ") );
 				} else if ( this.method ) {
-					code.insert( this.key.end, ": function" );
+					code.insert( this.key.end, (": function") );
 				}
@@ -711,14 +764,13 @@ }
 			this.method = this.findNearest( 'MethodDefinition' );
-			this.superClassName = this.findNearest( 'ClassBody' ).parent.superClass.name;
+			if ( !this.method ) throw new CompileError( this, 'use of super outside class method' );
 
-			if ( !this.method ) {
-				throw new Error( 'super outside method' ); // TODO location etc
-			}
+			var parentClass = this.findNearest( 'ClassBody' ).parent;
+			this.superClassName = parentClass.superClass && parentClass.superClass.name;
 
-			this.isCalled = this.parent.type === 'CallExpression';
+			if ( !this.superClassName ) throw new CompileError( this, 'super used in base class' );
 
-			if ( this.method.kind === 'constructor' ) {
-				if ( !this.isCalled ) throw new Error( 'super cannot be referred to in constructor outside a call expression' ); // TODO this is cryptic
-			} else {
-				if ( this.isCalled ) throw new Error( 'super() not allowed outside class constructor' );
+			this.isCalled = this.parent.type === 'CallExpression' && this === this.parent.callee;
+
+			if ( this.method.kind !== 'constructor' && this.isCalled ) {
+				throw new CompileError( this, 'super() not allowed outside class constructor' );
 			}
@@ -729,3 +781,3 @@
 			if ( !this.isCalled && !this.isMember ) {
-				throw new Error( 'Unexpected use of `super` (expected `super(...)` or `super.*`)' );
+				throw new CompileError( this, 'Unexpected use of `super` (expected `super(...)` or `super.*`)' );
 			}
@@ -735,3 +787,3 @@ };
 		Super.prototype.transpile = function transpile ( code ) {
-			var expression = this.isCalled ? this.superClassName : "" + (this.superClassName) + ".prototype";
+			var expression = this.isCalled ? this.superClassName : ("" + (this.superClassName) + ".prototype");
 			code.overwrite( this.start, this.end, expression, true );
@@ -745,5 +797,5 @@
 				if ( callExpression.arguments.length ) {
-					code.insert( callExpression.arguments[0].start, "this, " );
+					code.insert( callExpression.arguments[0].start, ("this, ") );
 				} else {
-					code.insert( callExpression.end - 1, "this" );
+					code.insert( callExpression.end - 1, ("this") );
 				}
@@ -765,3 +817,3 @@ }
 		TaggedTemplateExpression.prototype.initialise = function initialise () {
-			unsupported( this, 'Tagged template expressions are not supported' );
+			throw new CompileError( this.tag, 'Tagged template expressions are not supported' );
 		};
@@ -772,2 +824,17 @@
 
+	var TemplateElement = (function (Node) {
+		function TemplateElement () {
+			Node.apply(this, arguments);
+		}
+
+		TemplateElement.prototype = Object.create( Node && Node.prototype );
+		TemplateElement.prototype.constructor = TemplateElement;
+
+		TemplateElement.prototype.initialise = function initialise () {
+			this.program.templateElements.push( this );
+		};
+
+		return TemplateElement;
+	}(Node));
+
 	var TemplateLiteral = (function (Node) {
@@ -799,3 +866,3 @@ function TemplateLiteral () {
 					var stringified = JSON.stringify( node.value.cooked );
-					var replacement = ( closeParenthesis ? ')' : '' ) + ( ( node.tail && !node.value.cooked.length && i !== 0 ) ? '' : "" + (i ? ' + ' : '') + "" + stringified + "" );
+					var replacement = ( closeParenthesis ? ')' : '' ) + ( ( node.tail && !node.value.cooked.length && i !== 0 ) ? '' : ("" + (i ? ' + ' : '') + "" + stringified) );
 					code.overwrite( lastIndex, node.end, replacement );
@@ -863,4 +930,3 @@
 				if ( declaration && declaration.kind === 'const' ) {
-					// TODO location etc
-					throw new Error( "" + (this.argument.name) + " is read-only" );
+					throw new CompileError( this, ("" + (this.argument.name) + " is read-only") );
 				}
@@ -915,4 +981,4 @@ }
 				this.id[ this.isObjectPattern ? 'properties' : 'elements' ].forEach( function ( node ) {
-					if ( /Pattern/.test( this$1.isObjectPattern ? node.value.type : node.type ) ) {
-						unsupported( this$1, 'Compound destructuring is not supported' );
+					if ( node && /Pattern/.test( this$1.isObjectPattern ? node.value.type : node.type ) ) {
+						throw new CompileError( node.value, 'Compound destructuring is not supported' );
 					}
@@ -927,2 +993,4 @@ });
 		VariableDeclarator.prototype.transpile = function transpile ( code ) {
+			var this$1 = this;
+
 			if ( this.id.type !== 'Identifier' ) {
@@ -933,5 +1001,5 @@ var simple = this.init.type === 'Identifier';
 				if ( !simple ) {
-					code.insert( this.start, "" + name + " = " );
+					code.insert( this.start, ("" + name + " = ") );
 					code.move( this.init.start, this.init.end, this.start );
-					code.insert( this.start, ", " );
+					code.insert( this.start, (", ") );
 				} else {
@@ -945,11 +1013,17 @@ code.remove( this.init.start, this.init.end );
 
-				props.forEach( this.isObjectPattern ?
-					function ( property ) {
-						code.overwrite( property.start, property.end, "" + (property.value.name) + " = " + name + "." + (property.key.name) + "" );
-					} :
-					function ( property, i ) {
-						code.overwrite( property.start, property.end, "" + (property.name) + " = " + name + "[" + i + "]" );
-					});
+				var lastIndex = this.start;
+				var first = true;
 
-				code.remove( props[ props.length - 1 ].end, this.init.start );
+				props.forEach( function ( property, i ) {
+					if ( property ) {
+						var lhs = this$1.isObjectPattern ? property.value.name : property.name;
+						var rhs = this$1.isObjectPattern ? ("" + name + "." + (property.key.name)) : ("" + name + "[" + i + "]");
+
+						code.overwrite( lastIndex, property.end, ("" + (first ? '' : ', ') + "" + lhs + " = " + rhs) );
+						lastIndex = property.end;
+						first = false;
+					}
+				});
+
+				code.remove( lastIndex, this.init.start );
 			}
@@ -980,2 +1054,3 @@
 		TaggedTemplateExpression: TaggedTemplateExpression,
+		TemplateElement: TemplateElement,
 		TemplateLiteral: TemplateLiteral,
@@ -1029,4 +1104,3 @@ ThisExpression: ThisExpression,
 				if ( this$1.declarations[ name ] ) {
-					// TODO add location for debugging...
-					throw new Error( "" + name + " is already declared" );
+					throw new CompileError( node, ("" + name + " is already declared") );
 				}
@@ -1064,3 +1138,3 @@
 			while ( this.declarations[ name ] || this.references[ name ] || this.aliases[ name ] || name in reserved ) {
-				name = "" + base + "$" + (counter++) + "";
+				name = "" + base + "$" + (counter++);
 			}
@@ -1161,3 +1235,3 @@
 			if ( this.thisAlias ) {
-				if ( addedStuff ) code.insert( start, "\n" + indentation + "" );
+				if ( addedStuff ) code.insert( start, ("\n" + indentation) );
 				var assignment$1 = "var " + (this.thisAlias) + " = this;";
@@ -1173,9 +1247,9 @@ code.insert( start, assignment$1 );
 				params.filter( function ( param ) { return param.type === 'AssignmentPattern'; } ).forEach( function ( param ) {
-					if ( addedStuff ) code.insert( start, "\n" + indentation + "" );
+					if ( addedStuff ) code.insert( start, ("\n" + indentation) );
 
-					var lhs = "if ( " + (param.left.name) + " === void 0 ) " + (param.left.name) + "";
+					var lhs = "if ( " + (param.left.name) + " === void 0 ) " + (param.left.name);
 					code
-						.insert( start, "" + lhs + "" )
+						.insert( start, ("" + lhs) )
 						.move( param.left.end, param.right.end, start )
-						.insert( start, ";" );
+						.insert( start, (";") );
 
@@ -1195,3 +1269,3 @@ addedStuff = true;
 
-						if ( addedStuff ) code.insert( start, "\n" + indentation + "" );
+						if ( addedStuff ) code.insert( start, ("\n" + indentation) );
 
@@ -1205,3 +1279,3 @@ var key = prop.key.name;
 							var value = prop.value.name;
-							code.insert( start, "var " + value + " = " + ref + "." + key + ";" );
+							code.insert( start, ("var " + value + " = " + ref + "." + key + ";") );
 						} else if ( prop.value.type === 'AssignmentPattern' ) {
@@ -1213,9 +1287,9 @@ code.remove( prop.value.start, prop.value.right.start );
 							code
-								.insert( start, "var " + ref + "_" + key + " = ref." + key + ", " + value$1 + " = ref_" + key + " === void 0 ? " )
+								.insert( start, ("var " + ref + "_" + key + " = ref." + key + ", " + value$1 + " = ref_" + key + " === void 0 ? ") )
 								.move( prop.value.right.start, prop.value.right.end, start )
-								.insert( start, " : ref_" + key + ";" );
+								.insert( start, (" : ref_" + key + ";") );
 						}
 
 						else {
-							throw new Error( "" + (prop.type) + " not currently supported" ); // TODO...
+							throw new CompileError( prop, ("Compound destructuring is not supported") );
 						}
@@ -1240,3 +1314,3 @@
 
-						if ( addedStuff ) code.insert( start, "\n" + indentation + "" );
+						if ( addedStuff ) code.insert( start, ("\n" + indentation) );
 
@@ -1247,3 +1321,3 @@ if ( element.type === 'Identifier' ) {
 
-							code.insert( start, "var " + (element.name) + " = " + ref + "[" + i + "];" );
+							code.insert( start, ("var " + (element.name) + " = " + ref + "[" + i + "];") );
 						} else if ( element.type === 'AssignmentPattern' ) {
@@ -1255,9 +1329,9 @@ code.remove( element.start, element.right.start );
 							code
-								.insert( start, "var " + ref + "_" + i + " = ref[" + i + "], " + name + " = ref_" + i + " === void 0 ? " )
+								.insert( start, ("var " + ref + "_" + i + " = ref[" + i + "], " + name + " = ref_" + i + " === void 0 ? ") )
 								.move( element.right.start, element.right.end, start )
-								.insert( start, " : ref_" + i + ";" );
+								.insert( start, (" : ref_" + i + ";") );
 						}
 
 						else {
-							throw new Error( "" + (element.type) + " not currently supported" ); // TODO...
+							throw new CompileError( element, ("Compound destructuring is not supported") );
 						}
@@ -1284,3 +1358,3 @@
 
-					if ( addedStuff ) code.insert( start, "\n" + indentation + "" );
+					if ( addedStuff ) code.insert( start, ("\n" + indentation) );
 
@@ -1292,5 +1366,5 @@ var name = lastParam.argument.name;
 					if ( count ) {
-						code.insert( start, "var " + name + " = [], " + len + " = arguments.length - " + count + ";\n" + indentation + "while ( " + len + "-- > 0 ) " + name + "[ " + len + " ] = arguments[ " + len + " + " + count + " ];" );
+						code.insert( start, ("var " + name + " = [], " + len + " = arguments.length - " + count + ";\n" + indentation + "while ( " + len + "-- > 0 ) " + name + "[ " + len + " ] = arguments[ " + len + " + " + count + " ];") );
 					} else {
-						code.insert( start, "var " + name + " = [], " + len + " = arguments.length;\n" + indentation + "while ( " + len + "-- ) " + name + "[ " + len + " ] = arguments[ " + len + " ];" );
+						code.insert( start, ("var " + name + " = [], " + len + " = arguments.length;\n" + indentation + "while ( " + len + "-- ) " + name + "[ " + len + " ] = arguments[ " + len + " ];") );
 					}
@@ -1303,3 +1377,3 @@
 			if ( addedStuff ) {
-				code.insert( start, "\n\n" + indentation + "" );
+				code.insert( start, ("\n\n" + indentation) );
 			}
@@ -1311,3 +1385,3 @@
 
-					for ( var i = 0; i < declarations.length; i += 1 ) {
+					var forLoop = function ( i ) {
 						var declaration = declarations[i];
@@ -1321,3 +1395,5 @@ var alias = this$1.scope.createIdentifier( name );
 						}
-					}
+					};
+
+					for ( var i = 0; i < declarations.length; i += 1 ) forLoop( i );
 				});
@@ -1333,2 +1409,4 @@ }
 	function Program ( source, ast ) {
+		var this$1 = this;
+
 		this.type = 'Root';
@@ -1344,3 +1422,12 @@
 
+		this.templateElements = [];
 		this.body.initialise();
+
+		this.indentExclusions = {};
+		this.templateElements.forEach( function ( node ) {
+			for ( var i = node.start; i < node.end; i += 1 ) {
+				this$1.indentExclusions[ node.start + i ] = true;
+			}
+		});
+
 		this.body.transpile( this.magicString );
@@ -1373,11 +1460,16 @@ }
 	function transform ( source, options ) {
-		var ast = acorn.parse( source, {
-			ecmaVersion: 6,
-			preserveParens: true,
-			sourceType: 'module'
-		});
+		var ast;
 
-		var program = new Program( source, ast );
+		try {
+			ast = acorn.parse( source, {
+				ecmaVersion: 6,
+				preserveParens: true,
+				sourceType: 'module'
+			});
+		} catch ( err ) {
+			err.snippet = getSnippet( source, err.loc );
+			throw err;
+		}
 
-		return program.export( options );
+		return new Program( source, ast ).export( options );
 	}
@@ -1384,0 +1476,0 @@

package.json

 {
   "name": "buble",
-  "version": "0.4.5",
+  "version": "0.4.6",
   "description": "The blazing fast, batteries-included ES2015 compiler",
@@ -5,0 +5,0 @@ "main": "dist/buble.umd.js",

src/index.js

 import { parse } from 'acorn';
 import Program from './program/Program.js';
+import getSnippet from './utils/getSnippet.js';
 
 export function transform ( source, options ) {
-	var ast = parse( source, {
-		ecmaVersion: 6,
-		preserveParens: true,
-		sourceType: 'module'
-	});
+	let ast;
 
-	var program = new Program( source, ast );
+	try {
+		ast = parse( source, {
+			ecmaVersion: 6,
+			preserveParens: true,
+			sourceType: 'module'
+		});
+	} catch ( err ) {
+		err.snippet = getSnippet( source, err.loc );
+		throw err;
+	}
 
-	return program.export( options );
+	return new Program( source, ast ).export( options );
 }

src/program/BlockStatement.js

 import wrap from './wrap.js';
 import Node from './Node.js';
 import Scope from './Scope.js';
+import CompileError from '../utils/CompileError.js';
 
@@ -131,3 +132,3 @@ export default class BlockStatement extends Node {
 					else {
-						throw new Error( `${prop.type} not currently supported` ); // TODO...
+						throw new CompileError( prop, `Compound destructuring is not supported` );
 					}
@@ -171,3 +172,3 @@
 					else {
-						throw new Error( `${element.type} not currently supported` ); // TODO...
+						throw new CompileError( element, `Compound destructuring is not supported` );
 					}
@@ -174,0 +175,0 @@

src/program/Node.js

@@ -44,12 +44,2 @@ import { walk } from 'estree-walker';
 
-	findChildren ( type ) {
-		let children = [];
-		walk( this, {
-			enter ( node ) {
-				if ( node.type === type ) children.push( node );
-			}
-		});
-		return children;
-	}
-
 	findLexicalBoundary () {
@@ -79,3 +69,3 @@ return this.parent.findLexicalBoundary();
 			if ( Array.isArray( value ) ) {
-				value.forEach( node => node.initialise() );
+				value.forEach( node => node && node.initialise() );
 			} else if ( value && typeof value === 'object' ) {
@@ -96,3 +86,3 @@ value.initialise();
 			if ( Array.isArray( value ) ) {
-				value.forEach( node => node.transpile( code ) );
+				value.forEach( node => node && node.transpile( code ) );
 			} else if ( value && typeof value === 'object' ) {
@@ -99,0 +89,0 @@ value.transpile( code );

src/program/Program.js

@@ -15,3 +15,12 @@ import MagicString from 'magic-string';
 
+	this.templateElements = [];
 	this.body.initialise();
+
+	this.indentExclusions = {};
+	this.templateElements.forEach( node => {
+		for ( let i = node.start; i < node.end; i += 1 ) {
+			this.indentExclusions[ node.start + i ] = true;
+		}
+	});
+
 	this.body.transpile( this.magicString );
@@ -18,0 +27,0 @@ }

src/program/Scope.js

@@ -1,3 +0,3 @@
-//import Declaration from '../Declaration.js';
 import extractNames from './extractNames.js';
+import CompileError from '../utils/CompileError.js';
 
@@ -28,4 +28,3 @@ let reserved = Object.create( null );
 			if ( this.declarations[ name ] ) {
-				// TODO add location for debugging...
-				throw new Error( `${name} is already declared` );
+				throw new CompileError( node, `${name} is already declared` );
 			}
@@ -32,0 +31,0 @@

src/program/types/AssignmentExpression.js

 import Node from '../Node.js';
+import CompileError from '../../utils/CompileError.js';
 
@@ -8,4 +9,3 @@ export default class AssignmentExpression extends Node {
 			if ( declaration && declaration.kind === 'const' ) {
-				// TODO location etc
-				throw new Error( `${this.left.name} is read-only` );
+				throw new CompileError( this.left, `${this.left.name} is read-only` );
 			}
@@ -12,0 +12,0 @@ }

src/program/types/index.js

@@ -17,2 +17,3 @@ import AssignmentExpression from './AssignmentExpression.js';
 import TaggedTemplateExpression from './TaggedTemplateExpression.js';
+import TemplateElement from './TemplateElement.js';
 import TemplateLiteral from './TemplateLiteral.js';
@@ -41,2 +42,3 @@ import ThisExpression from './ThisExpression.js';
 	TaggedTemplateExpression,
+	TemplateElement,
 	TemplateLiteral,
@@ -43,0 +45,0 @@ ThisExpression,

src/program/types/Property.js

 import Node from '../Node.js';
-import unsupported from '../../utils/unsupported.js';
+import CompileError from '../../utils/CompileError.js';
 
@@ -7,3 +7,3 @@ export default class Property extends Node {
 		if ( this.computed ) {
-			unsupported( this, 'Computed properties are not supported' );
+			throw new CompileError( this.key, 'Computed properties are not supported' );
 		}
@@ -10,0 +10,0 @@

src/program/types/Super.js

 import Node from '../Node.js';
+import CompileError from '../../utils/CompileError.js';
 
@@ -6,14 +7,13 @@ export default class Super extends Node {
 		this.method = this.findNearest( 'MethodDefinition' );
-		this.superClassName = this.findNearest( 'ClassBody' ).parent.superClass.name;
+		if ( !this.method ) throw new CompileError( this, 'use of super outside class method' );
 
-		if ( !this.method ) {
-			throw new Error( 'super outside method' ); // TODO location etc
-		}
+		const parentClass = this.findNearest( 'ClassBody' ).parent;
+		this.superClassName = parentClass.superClass && parentClass.superClass.name;
 
-		this.isCalled = this.parent.type === 'CallExpression';
+		if ( !this.superClassName ) throw new CompileError( this, 'super used in base class' );
 
-		if ( this.method.kind === 'constructor' ) {
-			if ( !this.isCalled ) throw new Error( 'super cannot be referred to in constructor outside a call expression' ); // TODO this is cryptic
-		} else {
-			if ( this.isCalled ) throw new Error( 'super() not allowed outside class constructor' );
+		this.isCalled = this.parent.type === 'CallExpression' && this === this.parent.callee;
+
+		if ( this.method.kind !== 'constructor' && this.isCalled ) {
+			throw new CompileError( this, 'super() not allowed outside class constructor' );
 		}
@@ -24,3 +24,3 @@
 		if ( !this.isCalled && !this.isMember ) {
-			throw new Error( 'Unexpected use of `super` (expected `super(...)` or `super.*`)' );
+			throw new CompileError( this, 'Unexpected use of `super` (expected `super(...)` or `super.*`)' );
 		}
@@ -27,0 +27,0 @@ }

src/program/types/TaggedTemplateExpression.js

 import Node from '../Node.js';
-import unsupported from '../../utils/unsupported.js';
+import CompileError from '../../utils/CompileError.js';
 
 export default class TaggedTemplateExpression extends Node {
 	initialise () {
-		unsupported( this, 'Tagged template expressions are not supported' );
+		throw new CompileError( this.tag, 'Tagged template expressions are not supported' );
 	}
 }

src/program/types/UpdateExpression.js

 import Node from '../Node.js';
+import CompileError from '../../utils/CompileError.js';
 
@@ -8,4 +9,3 @@ export default class UpdateExpression extends Node {
 			if ( declaration && declaration.kind === 'const' ) {
-				// TODO location etc
-				throw new Error( `${this.argument.name} is read-only` );
+				throw new CompileError( this, `${this.argument.name} is read-only` );
 			}
@@ -12,0 +12,0 @@ }

src/program/types/VariableDeclarator.js

 import Node from '../Node.js';
-import unsupported from '../../utils/unsupported.js';
+import CompileError from '../../utils/CompileError.js';
 
@@ -11,4 +11,4 @@ export default class VariableDeclarator extends Node {
 			this.id[ this.isObjectPattern ? 'properties' : 'elements' ].forEach( node => {
-				if ( /Pattern/.test( this.isObjectPattern ? node.value.type : node.type ) ) {
-					unsupported( this, 'Compound destructuring is not supported' );
+				if ( node && /Pattern/.test( this.isObjectPattern ? node.value.type : node.type ) ) {
+					throw new CompileError( node.value, 'Compound destructuring is not supported' );
 				}
@@ -39,11 +39,17 @@ });
 
-			props.forEach( this.isObjectPattern ?
-				property => {
-					code.overwrite( property.start, property.end, `${property.value.name} = ${name}.${property.key.name}` );
-				} :
-				( property, i ) => {
-					code.overwrite( property.start, property.end, `${property.name} = ${name}[${i}]` );
-				});
+			let lastIndex = this.start;
+			let first = true;
 
-			code.remove( props[ props.length - 1 ].end, this.init.start );
+			props.forEach( ( property, i ) => {
+				if ( property ) {
+					const lhs = this.isObjectPattern ? property.value.name : property.name;
+					const rhs = this.isObjectPattern ? `${name}.${property.key.name}` : `${name}[${i}]`;
+
+					code.overwrite( lastIndex, property.end, `${first ? '' : ', '}${lhs} = ${rhs}` );
+					lastIndex = property.end;
+					first = false;
+				}
+			});
+
+			code.remove( lastIndex, this.init.start );
 		}
@@ -50,0 +56,0 @@

src/utils/deindent.js

@@ -12,9 +12,2 @@ // TODO this function is slightly flawed – it works on the original string,
 
-	let isExcluded = {};
-	node.findChildren( 'TemplateLiteral' ).forEach( node => {
-		for ( let i = node.start; i < node.end; i += 1 ) {
-			isExcluded[i] = true;
-		}
-	});
-
 	if ( code.original.slice( start - indentStr.length, start ) === indentStr ) {
@@ -27,4 +20,4 @@ code.remove( start - indentStr.length, start );
 	while ( match = pattern.exec( slice ) ) {
-		if ( !isExcluded[ match.index ] ) code.remove( start + match.index, start + match.index + indentStr.length );
+		if ( !node.program.indentExclusions[ match.index ] ) code.remove( start + match.index, start + match.index + indentStr.length );
 	}
 }

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Improved metrics

Total package byte prevSize

295685

increased by34.99%

Number of package files

43

increased by7.5%

Lines of code

3168

increased by5.88%

No dependency changes