@babel/plugin-transform-for-of - npm Package Compare versions

Comparing version 7.0.0-beta.32 to 7.0.0-beta.33

lib/index.js

@@ -9,3 +9,48 @@ "use strict";
 function _default(api, options) {
-  var loose = options.loose;
+  var loose = options.loose,
+      assumeArray = options.assumeArray;
+
+  if (loose === true && assumeArray === true) {
+    throw new Error("The loose and assumeArray options cannot be used together in @babel/plugin-transform-for-of");
+  }
+
+  if (assumeArray) {
+    return {
+      visitor: {
+        ForOfStatement: function ForOfStatement(path) {
+          var scope = path.scope;
+          var _path$node = path.node,
+              left = _path$node.left,
+              right = _path$node.right,
+              body = _path$node.body;
+          var i = scope.generateUidIdentifier("i");
+          var array = scope.maybeGenerateMemoised(right, true);
+          var inits = [_core.types.variableDeclarator(i, _core.types.numericLiteral(0))];
+
+          if (array) {
+            inits.push(_core.types.variableDeclarator(array, right));
+          } else {
+            array = right;
+          }
+
+          var item = _core.types.memberExpression(array, _core.types.clone(i), true);
+
+          var assignment;
+
+          if (_core.types.isVariableDeclaration(left)) {
+            assignment = left;
+            assignment.declarations[0].init = item;
+          } else {
+            assignment = _core.types.expressionStatement(_core.types.assignmentExpression("=", left, item));
+          }
+
+          var block = _core.types.toBlock(body);
+
+          block.body.unshift(assignment);
+          path.replaceWith(_core.types.forStatement(_core.types.variableDeclaration("let", inits), _core.types.binaryExpression("<", _core.types.clone(i), _core.types.memberExpression(_core.types.clone(array), _core.types.identifier("length"))), _core.types.updateExpression("++", _core.types.clone(i)), block));
+        }
+      }
+    };
+  }
+
   var pushComputedProps = loose ? pushComputedPropsLoose : pushComputedPropsSpec;
@@ -12,0 +57,0 @@ var buildForOfArray = (0, _core.template)("\n    for (var KEY = 0; KEY < ARR.length; KEY++) BODY;\n  ");

package.json

 {
   "name": "@babel/plugin-transform-for-of",
-  "version": "7.0.0-beta.32",
+  "version": "7.0.0-beta.33",
   "description": "Compile ES2015 for...of to ES5",
@@ -12,8 +12,8 @@ "repository": "https://github.com/babel/babel/tree/master/packages/babel-plugin-transform-for-of",
   "peerDependencies": {
-    "@babel/core": "7.0.0-beta.32"
+    "@babel/core": "7.0.0-beta.33"
   },
   "devDependencies": {
-    "@babel/core": "7.0.0-beta.32",
-    "@babel/helper-plugin-test-runner": "7.0.0-beta.32"
+    "@babel/core": "7.0.0-beta.33",
+    "@babel/helper-plugin-test-runner": "7.0.0-beta.33"
   }
 }

README.md

@@ -56,3 +56,3 @@ # @babel/plugin-transform-for-of
 {
-  "plugins": ["@babel/transform-for-of"]
+  "plugins": ["@babel/plugin-transform-for-of"]
 }
@@ -63,7 +63,8 @@ ```
 
-```json
+```js
 {
   "plugins": [
-    ["@babel/transform-for-of", {
-      "loose": true
+    ["@babel/plugin-transform-for-of", {
+      "loose": true, // defaults to false
+      "assumeArray": true // defaults to false
     }]
@@ -77,3 +78,3 @@ ]
 ```sh
-babel --plugins @babel/transform-for-of script.js
+babel --plugins @babel/plugin-transform-for-of script.js
 ```
@@ -85,3 +86,3 @@
 require("@babel/core").transform("code", {
-  plugins: ["@babel/transform-for-of"]
+  plugins: ["@babel/plugin-transform-for-of"]
 });
@@ -133,2 +134,9 @@ ```
 
+### `assumeArray`
+`boolean`, defaults to `false`
+
+This will apply the optimization shown below to all for-of loops by assuming that _all_ loops are arrays.
+
+Can be useful when you just want a for-of loop to represent a basic for loop over an array.
+
 ### Optimization
@@ -135,0 +143,0 @@

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Improved metrics

Total package byte prevSize

12038

increased by20.4%

Lines of code

193

increased by23.72%

Number of lines in readme file

155

increased by5.44%

No dependency changes