Sticky RegExp 'y' and RegExp#test delegation (#732)

Sticky RegExp 'y' and RegExp#test delegation, close #372, close #492

packages/core-js-compat/src/data.js

@@ -806,15 +806,26 @@ const data = {
   },
   'es.regexp.exec': {
     chrome: '26',
-    firefox: '4',
-    ie: '9',
-    safari: '8.0',
+    firefox: '44',
+    edge: '13',
+    safari: '10.0',
   },
   'es.regexp.flags': {
     chrome: '49',
     firefox: '37',
     safari: '9.0',
   },
+  'es.regexp.sticky': {
+    chrome: '49',
+    edge: '13',
+    firefox: '3',
+    safari: '10.0',
+  },
+  'es.regexp.test': {
+    chrome: '51',
+    firefox: '46',
+    safari: '10.0',
+  },
   'es.regexp.to-string': {
     chrome: '50',
     firefox: '46',

packages/core-js/es/index.js

@@ -105,6 +105,8 @@ require('../modules/es.string.sup');
 require('../modules/es.regexp.constructor');
 require('../modules/es.regexp.exec');
 require('../modules/es.regexp.flags');
+require('../modules/es.regexp.sticky');
+require('../modules/es.regexp.test');
 require('../modules/es.regexp.to-string');
 require('../modules/es.parse-int');
 require('../modules/es.parse-float');

packages/core-js/es/regexp/index.js

@@ -2,6 +2,8 @@ require('../../modules/es.regexp.constructor');
 require('../../modules/es.regexp.to-string');
 require('../../modules/es.regexp.exec');
 require('../../modules/es.regexp.flags');
+require('../../modules/es.regexp.sticky');
+require('../../modules/es.regexp.test');
 require('../../modules/es.string.match');
 require('../../modules/es.string.replace');
 require('../../modules/es.string.search');

packages/core-js/es/regexp/sticky.js

@@ -0,0 +1,5 @@
+require('../../modules/es.regexp.sticky');
+
+module.exports = function (it) {
+  return it.sticky;
+};

packages/core-js/internals/fix-regexp-well-known-symbol-logic.js

@@ -1,9 +1,9 @@
 'use strict';
-var createNonEnumerableProperty = require('../internals/create-non-enumerable-property');
 var redefine = require('../internals/redefine');
 var fails = require('../internals/fails');
 var wellKnownSymbol = require('../internals/well-known-symbol');
 var regexpExec = require('../internals/regexp-exec');
+var createNonEnumerableProperty = require('../internals/create-non-enumerable-property');
 
 var SPECIES = wellKnownSymbol('species');
 
@@ -20,6 +20,12 @@ var REPLACE_SUPPORTS_NAMED_GROUPS = !fails(function () {
   return ''.replace(re, '$<a>') !== '7';
 });
 
+// IE <= 11 replaces $0 with the whole match, as if it was $&
+// https://stackoverflow.com/questions/6024666/getting-ie-to-replace-a-regex-with-the-literal-string-0
+var REPLACE_KEEPS_$0 = (function () {
+  return 'a'.replace(/./, '$0') === '$0';
+})();
+
 // Chrome 51 has a buggy "split" implementation when RegExp#exec !== nativeExec
 // Weex JS has frozen built-in prototypes, so use try / catch wrapper
 var SPLIT_WORKS_WITH_OVERWRITTEN_EXEC = !fails(function () {
@@ -67,7 +73,7 @@ module.exports = function (KEY, length, exec, sham) {
   if (
     !DELEGATES_TO_SYMBOL ||
     !DELEGATES_TO_EXEC ||
-    (KEY === 'replace' && !REPLACE_SUPPORTS_NAMED_GROUPS) ||
+    (KEY === 'replace' && !(REPLACE_SUPPORTS_NAMED_GROUPS && REPLACE_KEEPS_$0)) ||
     (KEY === 'split' && !SPLIT_WORKS_WITH_OVERWRITTEN_EXEC)
   ) {
     var nativeRegExpMethod = /./[SYMBOL];
@@ -82,7 +88,7 @@ module.exports = function (KEY, length, exec, sham) {
         return { done: true, value: nativeMethod.call(str, regexp, arg2) };
       }
       return { done: false };
-    });
+    }, { REPLACE_KEEPS_$0: REPLACE_KEEPS_$0 });
     var stringMethod = methods[0];
     var regexMethod = methods[1];
 
@@ -95,6 +101,7 @@ module.exports = function (KEY, length, exec, sham) {
       // 21.2.5.9 RegExp.prototype[@@search](string)
       : function (string) { return regexMethod.call(string, this); }
     );
-    if (sham) createNonEnumerableProperty(RegExp.prototype[SYMBOL], 'sham', true);
   }
+
+  if (sham) createNonEnumerableProperty(RegExp.prototype[SYMBOL], 'sham', true);
 };

packages/core-js/internals/regexp-exec.js

@@ -1,5 +1,6 @@
 'use strict';
 var regexpFlags = require('./regexp-flags');
+var stickyHelpers = require('./regexp-sticky-helpers');
 
 var nativeExec = RegExp.prototype.exec;
 // This always refers to the native implementation, because the
@@ -17,24 +18,56 @@ var UPDATES_LAST_INDEX_WRONG = (function () {
   return re1.lastIndex !== 0 || re2.lastIndex !== 0;
 })();
 
+var UNSUPPORTED_Y = stickyHelpers.UNSUPPORTED_Y || stickyHelpers.BROKEN_CARET;
+
 // nonparticipating capturing group, copied from es5-shim's String#split patch.
 var NPCG_INCLUDED = /()??/.exec('')[1] !== undefined;
 
-var PATCH = UPDATES_LAST_INDEX_WRONG || NPCG_INCLUDED;
+var PATCH = UPDATES_LAST_INDEX_WRONG || NPCG_INCLUDED || UNSUPPORTED_Y;
 
 if (PATCH) {
   patchedExec = function exec(str) {
     var re = this;
     var lastIndex, reCopy, match, i;
+    var sticky = UNSUPPORTED_Y && re.sticky;
+    var flags = regexpFlags.call(re);
+    var source = re.source;
+    var charsAdded = 0;
+    var strCopy = str;
+
+    if (sticky) {
+      flags = flags.replace('y', '');
+      if (flags.indexOf('g') === -1) {
+        flags += 'g';
+      }
+
+      strCopy = String(str).slice(re.lastIndex);
+      // Support anchored sticky behavior.
+      if (re.lastIndex > 0 && (!re.multiline || re.multiline && str[re.lastIndex - 1] !== '\n')) {
+        source = '(?: ' + source + ')';
+        strCopy = ' ' + strCopy;
+        charsAdded++;
+      }
+      // ^(? + rx + ) is needed, in combination with some str slicing, to
+      // simulate the 'y' flag.
+      reCopy = new RegExp('^(?:' + source + ')', flags);
+    }
 
     if (NPCG_INCLUDED) {
-      reCopy = new RegExp('^' + re.source + '$(?!\\s)', regexpFlags.call(re));
+      reCopy = new RegExp('^' + source + '$(?!\\s)', flags);
     }
     if (UPDATES_LAST_INDEX_WRONG) lastIndex = re.lastIndex;
 
-    match = nativeExec.call(re, str);
+    match = nativeExec.call(sticky ? reCopy : re, strCopy);
 
-    if (UPDATES_LAST_INDEX_WRONG && match) {
+    if (sticky) {
+      if (match) {
+        match.input = match.input.slice(charsAdded);
+        match[0] = match[0].slice(charsAdded);
+        match.index = re.lastIndex;
+        re.lastIndex += match[0].length;
+      } else re.lastIndex = 0;
+    } else if (UPDATES_LAST_INDEX_WRONG && match) {
       re.lastIndex = re.global ? match.index + match[0].length : lastIndex;
     }
     if (NPCG_INCLUDED && match && match.length > 1) {

packages/core-js/internals/regexp-sticky-helpers.js

@@ -0,0 +1,23 @@
+'use strict';
+
+var fails = require('./fails');
+
+// babel-minify transpiles RegExp('a', 'y') -> /a/y and it causes SyntaxError,
+// so we use an intermediate function.
+function RE(s, f) {
+  return RegExp(s, f);
+}
+
+exports.UNSUPPORTED_Y = fails(function () {
+  // babel-minify transpiles RegExp('a', 'y') -> /a/y and it causes SyntaxError
+  var re = RE('a', 'y');
+  re.lastIndex = 2;
+  return re.exec('abcd') != null;
+});
+
+exports.BROKEN_CARET = fails(function () {
+  // https://bugzilla.mozilla.org/show_bug.cgi?id=773687
+  var re = RE('^r', 'gy');
+  re.lastIndex = 2;
+  return re.exec('str') != null;
+});

packages/core-js/modules/es.regexp.constructor.js

@@ -6,8 +6,10 @@ var defineProperty = require('../internals/object-define-property').f;
 var getOwnPropertyNames = require('../internals/object-get-own-property-names').f;
 var isRegExp = require('../internals/is-regexp');
 var getFlags = require('../internals/regexp-flags');
+var stickyHelpers = require('../internals/regexp-sticky-helpers');
 var redefine = require('../internals/redefine');
 var fails = require('../internals/fails');
+var setInternalState = require('../internals/internal-state').set;
 var setSpecies = require('../internals/set-species');
 var wellKnownSymbol = require('../internals/well-known-symbol');
 
@@ -20,7 +22,9 @@ var re2 = /a/g;
 // "new" should create a new object, old webkit bug
 var CORRECT_NEW = new NativeRegExp(re1) !== re1;
 
-var FORCED = DESCRIPTORS && isForced('RegExp', (!CORRECT_NEW || fails(function () {
+var UNSUPPORTED_Y = stickyHelpers.UNSUPPORTED_Y;
+
+var FORCED = DESCRIPTORS && isForced('RegExp', (!CORRECT_NEW || UNSUPPORTED_Y || fails(function () {
   re2[MATCH] = false;
   // RegExp constructor can alter flags and IsRegExp works correct with @@match
   return NativeRegExp(re1) != re1 || NativeRegExp(re2) == re2 || NativeRegExp(re1, 'i') != '/a/i';
@@ -33,13 +37,32 @@ if (FORCED) {
     var thisIsRegExp = this instanceof RegExpWrapper;
     var patternIsRegExp = isRegExp(pattern);
     var flagsAreUndefined = flags === undefined;
-    return !thisIsRegExp && patternIsRegExp && pattern.constructor === RegExpWrapper && flagsAreUndefined ? pattern
-      : inheritIfRequired(CORRECT_NEW
-        ? new NativeRegExp(patternIsRegExp && !flagsAreUndefined ? pattern.source : pattern, flags)
-        : NativeRegExp((patternIsRegExp = pattern instanceof RegExpWrapper)
-          ? pattern.source
-          : pattern, patternIsRegExp && flagsAreUndefined ? getFlags.call(pattern) : flags)
-      , thisIsRegExp ? this : RegExpPrototype, RegExpWrapper);
+
+    if (!thisIsRegExp && patternIsRegExp && pattern.constructor === RegExpWrapper && flagsAreUndefined) {
+      return pattern;
+    }
+
+    if (CORRECT_NEW) {
+      if (patternIsRegExp && !flagsAreUndefined) pattern = pattern.source;
+    } else if (pattern instanceof RegExpWrapper) {
+      if (flagsAreUndefined) flags = getFlags.call(pattern);
+      pattern = pattern.source;
+    }
+
+    if (UNSUPPORTED_Y) {
+      var sticky = !!flags && flags.indexOf('y') > -1;
+      if (sticky) flags = flags.replace(/y/g, '');
+    }
+
+    var result = inheritIfRequired(
+      CORRECT_NEW ? new NativeRegExp(pattern, flags) : NativeRegExp(pattern, flags),
+      thisIsRegExp ? this : RegExpPrototype,
+      RegExpWrapper
+    );
+
+    if (UNSUPPORTED_Y) setInternalState(result, { sticky: sticky });
+
+    return result;
   };
   var proxy = function (key) {
     key in RegExpWrapper || defineProperty(RegExpWrapper, key, {

packages/core-js/modules/es.regexp.flags.js

@@ -1,10 +1,11 @@
 var DESCRIPTORS = require('../internals/descriptors');
 var objectDefinePropertyModule = require('../internals/object-define-property');
 var regExpFlags = require('../internals/regexp-flags');
+var UNSUPPORTED_Y = require('../internals/regexp-sticky-helpers').UNSUPPORTED_Y;
 
 // `RegExp.prototype.flags` getter
 // https://tc39.github.io/ecma262/#sec-get-regexp.prototype.flags
-if (DESCRIPTORS && /./g.flags != 'g') {
+if (DESCRIPTORS && (/./g.flags != 'g' || UNSUPPORTED_Y)) {
   objectDefinePropertyModule.f(RegExp.prototype, 'flags', {
     configurable: true,
     get: regExpFlags

packages/core-js/modules/es.regexp.sticky.js

@@ -0,0 +1,21 @@
+var DESCRIPTORS = require('../internals/descriptors');
+var UNSUPPORTED_Y = require('../internals/regexp-sticky-helpers').UNSUPPORTED_Y;
+var defineProperty = require('../internals/object-define-property').f;
+var getInternalState = require('../internals/internal-state').get;
+var RegExpPrototype = RegExp.prototype;
+
+// `RegExp.prototype.sticky` getter
+if (DESCRIPTORS && UNSUPPORTED_Y) {
+  defineProperty(RegExp.prototype, 'sticky', {
+    configurable: true,
+    get: function () {
+      if (this === RegExpPrototype) return undefined;
+      // We can't use InternalStateModule.getterFor because
+      // we don't add metadata for regexps created by a literal.
+      if (this instanceof RegExp) {
+        return !!getInternalState(this).sticky;
+      }
+      throw TypeError('Incompatible receiver, RegExp required');
+    }
+  });
+}

packages/core-js/modules/es.regexp.test.js

@@ -0,0 +1,28 @@
+'use strict';
+var $ = require('../internals/export');
+var isObject = require('../internals/is-object');
+
+var DELEGATES_TO_EXEC = function () {
+  var execCalled = false;
+  var re = /[ac]/;
+  re.exec = function () {
+    execCalled = true;
+    return /./.exec.apply(this, arguments);
+  };
+  return re.test('abc') === true && execCalled;
+}();
+
+var nativeTest = /./.test;
+
+$({ target: 'RegExp', proto: true, forced: !DELEGATES_TO_EXEC }, {
+  test: function (str) {
+    if (typeof this.exec !== 'function') {
+      return nativeTest.call(this, str);
+    }
+    var result = this.exec(str);
+    if (result !== null && !isObject(result)) {
+      throw new Error('RegExp exec method returned something other than an Object or null');
+    }
+    return !!result;
+  }
+});

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

@@ -19,7 +19,7 @@ var maybeToString = function (it) {
 };
 
 // @@replace logic
-fixRegExpWellKnownSymbolLogic('replace', 2, function (REPLACE, nativeReplace, maybeCallNative) {
+fixRegExpWellKnownSymbolLogic('replace', 2, function (REPLACE, nativeReplace, maybeCallNative, reason) {
   return [
     // `String.prototype.replace` method
     // https://tc39.github.io/ecma262/#sec-string.prototype.replace
@@ -33,8 +33,14 @@ fixRegExpWellKnownSymbolLogic('replace', 2, function (REPLACE, nativeReplace, ma
     // `RegExp.prototype[@@replace]` method
     // https://tc39.github.io/ecma262/#sec-regexp.prototype-@@replace
     function (regexp, replaceValue) {
-      var res = maybeCallNative(nativeReplace, regexp, this, replaceValue);
-      if (res.done) return res.value;
+      if (
+        reason.REPLACE_KEEPS_$0 || (
+          typeof replaceValue === 'string' && replaceValue.indexOf('$0') === -1
+        )
+      ) {
+        var res = maybeCallNative(nativeReplace, regexp, this, replaceValue);
+        if (res.done) return res.value;
+      }
 
       var rx = anObject(regexp);
       var S = String(this);

tests/compat/tests.js

@@ -733,18 +733,37 @@ GLOBAL.tests = {
       && RegExp(re1) === re1
       && RegExp(re2) !== re2
       && RegExp(re1, 'i') == '/a/i'
+      && new RegExp('a', 'y') // just check that it doesn't throw
       && RegExp[Symbol.species];
   },
   'es.regexp.exec': function () {
     var re1 = /a/;
     var re2 = /b*/g;
+    var reSticky = new RegExp('a', 'y');
+    var reStickyAnchored = new RegExp('^a', 'y');
     re1.exec('a');
     re2.exec('a');
     return re1.lastIndex === 0 && re2.lastIndex === 0
-      && /()??/.exec('')[1] === undefined;
+      && /()??/.exec('')[1] === undefined
+      && reSticky.exec('abc')[0] === 'a'
+      && reSticky.exec('abc') === null
+      && (reSticky.lastIndex = 1, reSticky.exec('bac')[0] === 'a')
+      && (reStickyAnchored.lastIndex = 2, reStickyAnchored.exec('cba') === null);
   },
   'es.regexp.flags': function () {
-    return /./g.flags === 'g';
+    return /./g.flags === 'g' && new RegExp('a', 'y').flags === 'y';
+  },
+  'es.regexp.sticky': function () {
+    return new RegExp('a', 'y').sticky === true;
+  },
+  'es.regexp.test': function () {
+    var execCalled = false;
+    var re = /[ac]/;
+    re.exec = function () {
+      execCalled = true;
+      return /./.exec.apply(this, arguments);
+    };
+    return re.test('abc') === true && execCalled;
   },
   'es.regexp.to-string': function () {
     return RegExp.prototype.toString.call({ source: 'a', flags: 'b' }) === '/a/b'