From db50b13a3e71b50017c9e5f9cf90c83346f6d98d Mon Sep 17 00:00:00 2001
From: Lauri Rooden <lauri@rooden.ee>
Date: Mon, 13 Nov 2023 13:17:56 +0200
Subject: [PATCH] add support to specify mangled name (#5815)

---
 README.md                   |  9 +++++++++
 lib/scope.js                |  8 +++++++-
 test/compress/keep_fargs.js | 14 ++++++++++++++
 3 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index e86f33d0589..ffd8344e84b 100644
--- a/README.md
+++ b/README.md
@@ -1029,6 +1029,15 @@ discarded by the compressor as not referenced.
 The safest comments where to place copyright information (or other info that
 needs to be kept in the output) are comments attached to toplevel nodes.
 
+### Specify preferred mangled name in comment annotations
+
+`/*@mangleTo:X*/` or `/*@mangleTo:X*/` comments allow you to choose the name.
+
+```javascript
+(function(one /*#mangleTo:H*/, two /*#mangleTo:i*/) { /*..*/ })(1, 2);
+// results (function(H,i){ /*..*/ )(1,2);
+```
+
 ### The `unsafe` `compress` option
 
 It enables some transformations that *might* break code logic in certain
diff --git a/lib/scope.js b/lib/scope.js
index 359c4f97da3..4ecf3ce83df 100644
--- a/lib/scope.js
+++ b/lib/scope.js
@@ -565,7 +565,13 @@ function next_mangled_name(def, options) {
             scopes.push(scope);
         } while (scope = scope.parent_scope);
     });
-    var name;
+    var comment = def.orig[0].start.comments_after[0]?.value;
+    var preferredName = comment && /[@#]mangleTo:(.*)/.exec(comment);
+    var name = preferredName && preferredName[1];
+    if (name && !names.has(name)) {
+        in_use.set(name, true);
+        return name;
+    }
     for (var i = 0; i < holes.length; i++) {
         name = base54(holes[i]);
         if (names.has(name)) continue;
diff --git a/test/compress/keep_fargs.js b/test/compress/keep_fargs.js
index a8e34cca580..900ca83b4d8 100644
--- a/test/compress/keep_fargs.js
+++ b/test/compress/keep_fargs.js
@@ -965,6 +965,20 @@ function_name_mangle: {
     expect_stdout: "function"
 }
 
+function_name_mangle_from_preferred_comment: {
+    options = {
+        keep_fargs: false,
+    }
+    mangle = {}
+    input: {
+        (function(one /*#mangleTo:W*/, two) {
+            console.log(one, two);
+        })(1, 2);
+    }
+    expect_exact: "(function(W,o){console.log(W,o)})(1,2);"
+    expect_stdout: "1 2"
+}
+
 function_name_mangle_ie8: {
     options = {
         keep_fargs: false,