fix #1349: quote modern unicode object properties

CHANGELOG.md

@@ -2,22 +2,27 @@
 
 ## Unreleased
 
-* Add support for ES5-style identifiers ([#1349](https://github.com/evanw/esbuild/issues/1349))
+* Quote object properties that are modern Unicode identifiers ([#1349](https://github.com/evanw/esbuild/issues/1349))
 
     In ES6 and above, an identifier is a character sequence starting with a character in the `ID_Start` Unicode category and followed by zero or more characters in the `ID_Continue` Unicode category, and these categories must be drawn from Unicode version 5.1 or above.
 
-    But in ES5, an identifier is a character sequence starting with a character in one of the `Lu, Ll, Lt, Lm, Lo, Nl` Unicode categories and followed by zero or more characters in the `Lu, Ll, Lt, Lm, Lo, Nl, Mn, Mc, Nd, Pc` Unicode categories, and these categories must be drawn from Unicode version 3.0.
+    But in ES5, an identifier is a character sequence starting with a character in one of the `Lu, Ll, Lt, Lm, Lo, Nl` Unicode categories and followed by zero or more characters in the `Lu, Ll, Lt, Lm, Lo, Nl, Mn, Mc, Nd, Pc` Unicode categories, and these categories must be drawn from Unicode version 3.0 or above.
 
-    Previously esbuild always used the ES6+ identifier validation test but with this release, it will use the ES5 validation test when the target environment doesn't support ES6+ identifiers. This identifier validation test is used in decisions related to code printing. For example:
+    Previously esbuild always used the ES6+ identifier validation test when deciding whether to use an identifier or a quoted string to encode an object property but with this release, it will use the ES5 validation test instead:
 
-    ```
-    $ echo x.ꓷꓶꓲꓵꓭꓢꓱ | ./esbuild --charset=utf8
-    x.ꓷꓶꓲꓵꓭꓢꓱ;
+    ```js
+    // Original code
+    x.ꓷꓶꓲꓵꓭꓢꓱ = { ꓷꓶꓲꓵꓭꓢꓱ: y };
 
-    $ echo x.ꓷꓶꓲꓵꓭꓢꓱ | ./esbuild --charset=utf8 --target=es5
-    x["ꓷꓶꓲꓵꓭꓢꓱ"];
+    // Old output
+    x.ꓷꓶꓲꓵꓭꓢꓱ = { ꓷꓶꓲꓵꓭꓢꓱ: y };
+
+    // New output
+    x["ꓷꓶꓲꓵꓭꓢꓱ"] = { "ꓷꓶꓲꓵꓭꓢꓱ": y };
     ```
 
+    This approach should ensure maximum compatibility with all JavaScript environments that support ES5 and above. Note that this means minified files containing Unicode properties may be slightly larger than before.
+
 ## 0.12.6
 
 * Improve template literal lowering transformation conformance ([#1327](https://github.com/evanw/esbuild/issues/1327))

internal/bundler/linker.go

@@ -1660,7 +1660,7 @@ func (c *linkerContext) generateCodeForLazyExport(sourceIndex uint32) {
 		clone.Properties = append(make([]js_ast.Property, 0, len(clone.Properties)), clone.Properties...)
 		for i, property := range clone.Properties {
 			if str, ok := property.Key.Data.(*js_ast.EString); ok &&
-				(!file.IsEntryPoint() || js_lexer.IsIdentifierUTF16(str.Value, 0) ||
+				(!file.IsEntryPoint() || js_lexer.IsIdentifierUTF16(str.Value) ||
 					!c.options.UnsupportedJSFeatures.Has(compat.ArbitraryModuleNamespaceNames)) {
 				name := js_lexer.UTF16ToString(str.Value)
 				exportRef := generateExport(name, name, property.ValueOrNil).ref
@@ -4178,7 +4178,7 @@ func (c *linkerContext) renameSymbolsInChunk(chunk *chunkInfo, filesInOrder []ui
 	}
 
 	// When we're not minifying, just append numbers to symbol names to avoid collisions
-	r := renamer.NewNumberRenamer(c.graph.Symbols, reservedNames, c.options.UnsupportedJSFeatures)
+	r := renamer.NewNumberRenamer(c.graph.Symbols, reservedNames)
 	nestedScopes := make(map[uint32][]*js_ast.Scope)
 
 	timer.Begin("Add top-level symbols")
@@ -4705,7 +4705,7 @@ func (c *linkerContext) generateGlobalNamePrefix() string {
 		join = ";"
 	}
 
-	if js_printer.CanQuoteIdentifier(prefix, c.options.UnsupportedJSFeatures, c.options.ASCIIOnly) {
+	if js_printer.CanEscapeIdentifier(prefix, c.options.UnsupportedJSFeatures, c.options.ASCIIOnly) {
 		if c.options.ASCIIOnly {
 			prefix = string(js_printer.QuoteIdentifier(nil, prefix, c.options.UnsupportedJSFeatures))
 		}
@@ -4717,7 +4717,7 @@ func (c *linkerContext) generateGlobalNamePrefix() string {
 
 	for _, name := range c.options.GlobalName[1:] {
 		oldPrefix := prefix
-		if js_printer.CanQuoteIdentifier(name, c.options.UnsupportedJSFeatures, c.options.ASCIIOnly) {
+		if js_printer.CanEscapeIdentifier(name, c.options.UnsupportedJSFeatures, c.options.ASCIIOnly) {
 			if c.options.ASCIIOnly {
 				name = string(js_printer.QuoteIdentifier(nil, name, c.options.UnsupportedJSFeatures))
 			}

internal/compat/js_table.go

@@ -79,7 +79,6 @@ const (
 	TemplateLiteral
 	TopLevelAwait
 	UnicodeEscapes
-	UpdatedIdentifiers
 )
 
 func (features JSFeature) Has(feature JSFeature) bool {
@@ -418,15 +417,6 @@ var jsTable = map[JSFeature]map[Engine][]int{
 		Node:    {4},
 		Safari:  {9},
 	},
-	UpdatedIdentifiers: {
-		Chrome:  {58},
-		Edge:    {14},
-		ES:      {2015},
-		Firefox: {52},
-		IOS:     {14},
-		Node:    {8},
-		Safari:  {14},
-	},
 }
 
 func isVersionLessThan(a []int, b []int) bool {