Fix for #810 (#1514)

Co-authored-by: Denis Pushkarev <zloirock@zloirock.ru>

Author: johnzhou721

CHANGELOG.md

@@ -32,6 +32,7 @@
 - Fixed named backreferences in `RegExp` NCG polyfill
 - Fixed some cases of `RegExp` NCG polyfill in combination with other types of groups
 - Fixed some cases of `RegExp` NCG polyfill in combination with `dotAll`
+- Fixed `String.prototype.replace` with `sticky` polyfill, [#810](https://github.com/zloirock/core-js/issues/810), [#1514](https://github.com/zloirock/core-js/issues/1514)
 - Fixed `RegExp` `sticky` polyfill with alternation
 - Fixed handling of some line terminators in case of `multiline` + `sticky` mode in `RegExp` polyfill
 - Fixed `.input` slicing on result object with `RegExp` `sticky` mode polyfill

packages/core-js/modules/es.string.replace.js

@@ -76,19 +76,20 @@ fixRegExpWellKnownSymbolLogic('replace', function (_, nativeReplace, maybeCallNa
       var rx = anObject(this);
       var S = toString(string);
 
+      var functionalReplace = isCallable(replaceValue);
+      if (!functionalReplace) replaceValue = toString(replaceValue);
+      var flags = toString(getRegExpFlags(rx));
+
       if (
         typeof replaceValue == 'string' &&
         !~stringIndexOf(replaceValue, UNSAFE_SUBSTITUTE) &&
-        !~stringIndexOf(replaceValue, '$<')
+        !~stringIndexOf(replaceValue, '$<') &&
+        !~stringIndexOf(flags, 'y')
       ) {
         var res = maybeCallNative(nativeReplace, rx, S, replaceValue);
         if (res.done) return res.value;
       }
 
-      var functionalReplace = isCallable(replaceValue);
-      if (!functionalReplace) replaceValue = toString(replaceValue);
-
-      var flags = toString(getRegExpFlags(rx));
       var global = !!~stringIndexOf(flags, 'g');
       var fullUnicode;
       if (global) {

tests/unit-global/es.string.replace.js

@@ -131,6 +131,8 @@ const run = assert => {
   assert.same('a'.replace(/(.)/, '$0'), '$0');
 
   assert.throws(() => ''.replace.call(Symbol('replace test'), /./, ''), 'throws on symbol context');
+
+  assert.same('.a'.replace(new RegExp('a', 'y'), '.'), '.a', 'Replacement for y');
 };
 
 QUnit.test('String#replace regression', run);