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Comparing version 5.17.1 to 5.17.2

CHANGELOG.md

 # Changelog
 
+## v5.17.2
+ - Be less conservative when detecting use-before-definition of `var` in hoisted functions.
+ - Support unusual (but perfectly valid) initializers of for-in and for-of loops.
+ - Fix issue where hoisted function would be dropped if it was after a `continue` statement
+
 ## v5.17.1
@@ -4,0 +9,0 @@ - Fix evaluating `.length` when the source array might've been mutated

lib/compress/inference.js

@@ -67,2 +67,3 @@ /***********************************************************************
   AST_False,
+  AST_ForIn,
   AST_Function,
@@ -716,2 +717,3 @@ AST_If,
     if (parent instanceof AST_Assign && parent.left === node) return node;
+    if (parent instanceof AST_ForIn && parent.init === node) return node;
 }
@@ -718,0 +720,0 @@

lib/compress/reduce-vars.js

@@ -80,2 +80,3 @@ /***********************************************************************
     AST_SymbolConst,
+    AST_SymbolDeclaration,
     AST_SymbolDefun,
@@ -96,2 +97,3 @@ AST_SymbolFunarg,
     walk,
+    walk_parent,
     walk_abort,
@@ -106,3 +108,3 @@ walk_body,
 
-import { lazy_op, is_modified } from "./inference.js";
+import { lazy_op, is_modified, is_lhs } from "./inference.js";
 import { INLINED, clear_flag } from "./compressor-flags.js";
@@ -546,17 +548,28 @@ import { read_property, has_break_or_continue, is_recursive_ref } from "./common.js";
 
-            // Detect `call_defun(); var used_in_defun = ...`
-            // Because `used_in_defun` can no longer be fixed
-            let found_defun = false;
+            // Detect `call_defun(); var used_in_defun = X`
+            // Because `used_in_defun` is not certainly X when it's defined after.
+            let found_defun_ref = false;
             let found_def_after_defun = false;
-            walk(parent, node => {
+            walk_parent(parent, (node, info) => {
                 if (node === defun) return true;
 
-                if (node instanceof AST_Symbol) {
-                    if (!found_defun && node.thedef === fname_def) {
-                        found_defun = true;
-                    } else if (found_defun && node.thedef === def) {
-                        found_def_after_defun = true;
-                        return walk_abort;
-                    }
+                // Step 1: find `call_defun()` or other refs to the defun
+                if (
+                    !found_defun_ref
+                    && node.thedef === fname_def
+                    && node instanceof AST_Symbol
+                ) {
+                    found_defun_ref = true;
                 }
+
+                // Step 2: if Step 1 occurred, find a var the defun uses
+                if (
+                    found_defun_ref
+                    && node.thedef === def
+                    && (node instanceof AST_SymbolDeclaration
+                        || is_lhs(node, info))
+                ) {
+                    found_def_after_defun = true;
+                    return walk_abort;
+                }
             });
@@ -563,0 +576,0 @@

lib/compress/tighten-body.js

@@ -1005,4 +1005,9 @@ /***********************************************************************
             if (stat instanceof AST_If) {
-                var ab = aborts(stat.body);
-                if (can_merge_flow(ab)) {
+                let ab, new_else;
+
+                ab = aborts(stat.body);
+                if (
+                    can_merge_flow(ab)
+                    && (new_else = as_statement_array_with_return(stat.body, ab))
+                ) {
                     if (ab.label) {
@@ -1014,3 +1019,2 @@ remove(ab.label.thedef.references, ab);
                     stat.condition = stat.condition.negate(compressor);
-                    var body = as_statement_array_with_return(stat.body, ab);
                     stat.body = make_node(AST_BlockStatement, stat, {
@@ -1020,3 +1024,3 @@ body: as_statement_array(stat.alternative).concat(extract_functions())
                     stat.alternative = make_node(AST_BlockStatement, stat, {
-                        body: body
+                        body: new_else
                     });
@@ -1027,4 +1031,7 @@ statements[i] = stat.transform(compressor);
 
-                var ab = aborts(stat.alternative);
-                if (can_merge_flow(ab)) {
+                ab = aborts(stat.alternative);
+                if (
+                    can_merge_flow(ab)
+                    && (new_else = as_statement_array_with_return(stat.alternative, ab))
+                ) {
                     if (ab.label) {
@@ -1038,5 +1045,4 @@ remove(ab.label.thedef.references, ab);
                     });
-                    var body = as_statement_array_with_return(stat.alternative, ab);
                     stat.alternative = make_node(AST_BlockStatement, stat.alternative, {
-                        body: body
+                        body: new_else
                     });
@@ -1156,3 +1162,7 @@ statements[i] = stat.transform(compressor);
         function as_statement_array_with_return(node, ab) {
-            var body = as_statement_array(node).slice(0, -1);
+            var body = as_statement_array(node);
+            if (ab !== body[body.length - 1]) {
+                return undefined;
+            }
+            body = body.slice(0, -1);
             if (ab.value) {
@@ -1159,0 +1169,0 @@ body.push(make_node(AST_SimpleStatement, ab.value, {

package.json

@@ -7,3 +7,3 @@ {
   "license": "BSD-2-Clause",
-  "version": "5.17.1",
+  "version": "5.17.2",
   "engines": {
@@ -10,0 +10,0 @@ "node": ">=10"

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Improved metrics

Total package byte prevSize

2082840

increased by0.08%

Lines of code

59236

increased by0.07%

No dependency changes