87 lines
2.8 KiB
JavaScript
87 lines
2.8 KiB
JavaScript
'use strict';
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var regexpFlags = require('./regexp-flags');
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var stickyHelpers = require('./regexp-sticky-helpers');
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var nativeExec = RegExp.prototype.exec;
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// This always refers to the native implementation, because the
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// String#replace polyfill uses ./fix-regexp-well-known-symbol-logic.js,
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// which loads this file before patching the method.
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var nativeReplace = String.prototype.replace;
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var patchedExec = nativeExec;
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var UPDATES_LAST_INDEX_WRONG = (function () {
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var re1 = /a/;
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var re2 = /b*/g;
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nativeExec.call(re1, 'a');
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nativeExec.call(re2, 'a');
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return re1.lastIndex !== 0 || re2.lastIndex !== 0;
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})();
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var UNSUPPORTED_Y = stickyHelpers.UNSUPPORTED_Y || stickyHelpers.BROKEN_CARET;
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// nonparticipating capturing group, copied from es5-shim's String#split patch.
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var NPCG_INCLUDED = /()??/.exec('')[1] !== undefined;
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var PATCH = UPDATES_LAST_INDEX_WRONG || NPCG_INCLUDED || UNSUPPORTED_Y;
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if (PATCH) {
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patchedExec = function exec(str) {
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var re = this;
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var lastIndex, reCopy, match, i;
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var sticky = UNSUPPORTED_Y && re.sticky;
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var flags = regexpFlags.call(re);
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var source = re.source;
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var charsAdded = 0;
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var strCopy = str;
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if (sticky) {
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flags = flags.replace('y', '');
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if (flags.indexOf('g') === -1) {
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flags += 'g';
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}
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strCopy = String(str).slice(re.lastIndex);
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// Support anchored sticky behavior.
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if (re.lastIndex > 0 && (!re.multiline || re.multiline && str[re.lastIndex - 1] !== '\n')) {
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source = '(?: ' + source + ')';
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strCopy = ' ' + strCopy;
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charsAdded++;
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}
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// ^(? + rx + ) is needed, in combination with some str slicing, to
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// simulate the 'y' flag.
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reCopy = new RegExp('^(?:' + source + ')', flags);
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}
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if (NPCG_INCLUDED) {
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reCopy = new RegExp('^' + source + '$(?!\\s)', flags);
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}
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if (UPDATES_LAST_INDEX_WRONG) lastIndex = re.lastIndex;
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match = nativeExec.call(sticky ? reCopy : re, strCopy);
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if (sticky) {
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if (match) {
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match.input = match.input.slice(charsAdded);
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match[0] = match[0].slice(charsAdded);
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match.index = re.lastIndex;
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re.lastIndex += match[0].length;
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} else re.lastIndex = 0;
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} else if (UPDATES_LAST_INDEX_WRONG && match) {
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re.lastIndex = re.global ? match.index + match[0].length : lastIndex;
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}
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if (NPCG_INCLUDED && match && match.length > 1) {
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// Fix browsers whose `exec` methods don't consistently return `undefined`
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// for NPCG, like IE8. NOTE: This doesn' work for /(.?)?/
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nativeReplace.call(match[0], reCopy, function () {
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for (i = 1; i < arguments.length - 2; i++) {
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if (arguments[i] === undefined) match[i] = undefined;
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}
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});
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}
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return match;
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};
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}
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module.exports = patchedExec;
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