From 8b5e048786ecb72364f1ff6ab4c7bc30a0ea7e06 Mon Sep 17 00:00:00 2001
From: Evan Wallace <evan.exe@gmail.com>
Date: Tue, 5 Jul 2022 23:21:12 -0400
Subject: [PATCH] follow-up to #2371

---
 CHANGELOG.md                                | 34 +++++++++++++++++++++
 internal/bundler/bundler_ts_test.go         | 27 +++++++++++-----
 internal/bundler/snapshots/snapshots_ts.txt | 21 +++++++++----
 internal/js_printer/js_printer.go           |  2 +-
 4 files changed, 70 insertions(+), 14 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8c354110c20..08666e5507d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,39 @@
 # Changelog
 
+## Unreleased
+
+* Fix generated TypeScript `enum` comments containing `*/` ([#2369](https://github.com/evanw/esbuild/issues/2369), [#2371](https://github.com/evanw/esbuild/pull/2371))
+
+    TypeScript `enum` values that are equal to a number or string literal are inlined (references to the enum are replaced with the literal value) and have a `/* ... */` comment after them with the original enum name to improve readability. However, this comment is omitted if the enum name contains the character sequence `*/` because that would end the comment early and cause a syntax error:
+
+    ```ts
+    // Original TypeScript
+    enum Foo { '/*' = 1, '*/' = 2 }
+    console.log(Foo['/*'], Foo['*/'])
+
+    // Generated JavaScript
+    console.log(1 /* /* */, 2);
+    ```
+
+    This was originally handled correctly when TypeScript `enum` inlining was initially implemented since it was only supported within a single file. However, when esbuild was later extended to support TypeScript `enum` inlining across files, this special case where the enum name contains `*/` was not handled in that new code. Starting with this release, esbuild will now handle enums with names containing `*/` correctly when they are inlined across files:
+
+    ```ts
+    // foo.ts
+    export enum Foo { '/*' = 1, '*/' = 2 }
+
+    // bar.ts
+    import { Foo } from './foo'
+    console.log(Foo['/*'], Foo['*/'])
+
+    // Old output (with --bundle --format=esm)
+    console.log(1 /* /* */, 2 /* */ */);
+
+    // New output (with --bundle --format=esm)
+    console.log(1 /* /* */, 2);
+    ```
+
+    This fix was contributed by [@magic-akari](https://github.com/magic-akari).
+
 ## 0.14.48
 
 * Enable using esbuild in Deno via WebAssembly ([#2323](https://github.com/evanw/esbuild/issues/2323))
diff --git a/internal/bundler/bundler_ts_test.go b/internal/bundler/bundler_ts_test.go
index 2d730302ac9..eb4f5ee93bd 100644
--- a/internal/bundler/bundler_ts_test.go
+++ b/internal/bundler/bundler_ts_test.go
@@ -223,18 +223,31 @@ func TestTSDeclareConstEnum(t *testing.T) {
 	})
 }
 
-func TestConstEnumComments(t *testing.T) {
+func TestTSConstEnumComments(t *testing.T) {
 	ts_suite.expectBundled(t, bundled{
 		files: map[string]string{
 			"/bar.ts": `
-			export const enum PRCD {
-				"*/%" = 14,
-			}
+				export const enum Foo {
+					"%/*" = 1,
+					"*/%" = 2,
+				}
 			`,
 			"/foo.ts": `
-			import { PRCD } from "./bar";
-
-			console.log(PRCD["*/%"]);
+				import { Foo } from "./bar";
+				const enum Bar {
+					"%/*" = 1,
+					"*/%" = 2,
+				}
+				console.log({
+					'should have comments': [
+						Foo["%/*"],
+						Bar["%/*"],
+					],
+					'should not have comments': [
+						Foo["*/%"],
+						Bar["*/%"],
+					],
+				});
 			`,
 		},
 		entryPaths: []string{"/foo.ts"},
diff --git a/internal/bundler/snapshots/snapshots_ts.txt b/internal/bundler/snapshots/snapshots_ts.txt
index 49ff10f6b79..25bf5c03fcc 100644
--- a/internal/bundler/snapshots/snapshots_ts.txt
+++ b/internal/bundler/snapshots/snapshots_ts.txt
@@ -1,9 +1,3 @@
-TestConstEnumComments
----------- /out.js ----------
-// foo.ts
-console.log(14);
-
-================================================================================
 TestExportTypeIssue379
 ---------- /out.js ----------
 // a.ts
@@ -37,6 +31,21 @@ var foo4 = 123;
 // entry.ts
 console.log(a_exports, b_exports, c_exports, d_exports);
 
+================================================================================
+TestTSConstEnumComments
+---------- /out.js ----------
+// foo.ts
+console.log({
+  "should have comments": [
+    1 /* %/* */,
+    1 /* %/* */
+  ],
+  "should not have comments": [
+    2,
+    2
+  ]
+});
+
 ================================================================================
 TestTSDeclareClass
 ---------- /out.js ----------
diff --git a/internal/js_printer/js_printer.go b/internal/js_printer/js_printer.go
index cb9e2d6f0e2..e0f77992385 100644
--- a/internal/js_printer/js_printer.go
+++ b/internal/js_printer/js_printer.go
@@ -1940,7 +1940,7 @@ func (p *printer) printExpr(expr js_ast.Expr, level js_ast.L, flags printExprFla
 							} else {
 								p.printNumber(value.Number, level)
 							}
-							if !p.options.MinifyWhitespace && !p.options.MinifyIdentifiers {
+							if !p.options.MinifyWhitespace && !p.options.MinifyIdentifiers && !strings.Contains(e.Name, "*/") {
 								p.print(" /* ")
 								p.print(e.Name)
 								p.print(" */")