es6.regexp.split.js
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'use strict';
var isRegExp = require('./_is-regexp');
var anObject = require('./_an-object');
var speciesConstructor = require('./_species-constructor');
var advanceStringIndex = require('./_advance-string-index');
var toLength = require('./_to-length');
var callRegExpExec = require('./_regexp-exec-abstract');
var regexpExec = require('./_regexp-exec');
var fails = require('./_fails');
var $min = Math.min;
var $push = [].push;
var $SPLIT = 'split';
var LENGTH = 'length';
var LAST_INDEX = 'lastIndex';
var MAX_UINT32 = 0xffffffff;
// babel-minify transpiles RegExp('x', 'y') -> /x/y and it causes SyntaxError
var SUPPORTS_Y = !fails(function () { RegExp(MAX_UINT32, 'y'); });
// @@split logic
require('./_fix-re-wks')('split', 2, function (defined, SPLIT, $split, maybeCallNative) {
var internalSplit;
if (
'abbc'[$SPLIT](/(b)*/)[1] == 'c' ||
'test'[$SPLIT](/(?:)/, -1)[LENGTH] != 4 ||
'ab'[$SPLIT](/(?:ab)*/)[LENGTH] != 2 ||
'.'[$SPLIT](/(.?)(.?)/)[LENGTH] != 4 ||
'.'[$SPLIT](/()()/)[LENGTH] > 1 ||
''[$SPLIT](/.?/)[LENGTH]
) {
// based on es5-shim implementation, need to rework it
internalSplit = function (separator, limit) {
var string = String(this);
if (separator === undefined && limit === 0) return [];
// If `separator` is not a regex, use native split
if (!isRegExp(separator)) return $split.call(string, separator, limit);
var output = [];
var flags = (separator.ignoreCase ? 'i' : '') +
(separator.multiline ? 'm' : '') +
(separator.unicode ? 'u' : '') +
(separator.sticky ? 'y' : '');
var lastLastIndex = 0;
var splitLimit = limit === undefined ? MAX_UINT32 : limit >>> 0;
// Make `global` and avoid `lastIndex` issues by working with a copy
var separatorCopy = new RegExp(separator.source, flags + 'g');
var match, lastIndex, lastLength;
while (match = regexpExec.call(separatorCopy, string)) {
lastIndex = separatorCopy[LAST_INDEX];
if (lastIndex > lastLastIndex) {
output.push(string.slice(lastLastIndex, match.index));
if (match[LENGTH] > 1 && match.index < string[LENGTH]) $push.apply(output, match.slice(1));
lastLength = match[0][LENGTH];
lastLastIndex = lastIndex;
if (output[LENGTH] >= splitLimit) break;
}
if (separatorCopy[LAST_INDEX] === match.index) separatorCopy[LAST_INDEX]++; // Avoid an infinite loop
}
if (lastLastIndex === string[LENGTH]) {
if (lastLength || !separatorCopy.test('')) output.push('');
} else output.push(string.slice(lastLastIndex));
return output[LENGTH] > splitLimit ? output.slice(0, splitLimit) : output;
};
// Chakra, V8
} else if ('0'[$SPLIT](undefined, 0)[LENGTH]) {
internalSplit = function (separator, limit) {
return separator === undefined && limit === 0 ? [] : $split.call(this, separator, limit);
};
} else {
internalSplit = $split;
}
return [
// `String.prototype.split` method
// https://tc39.github.io/ecma262/#sec-string.prototype.split
function split(separator, limit) {
var O = defined(this);
var splitter = separator == undefined ? undefined : separator[SPLIT];
return splitter !== undefined
? splitter.call(separator, O, limit)
: internalSplit.call(String(O), separator, limit);
},
// `RegExp.prototype[@@split]` method
// https://tc39.github.io/ecma262/#sec-regexp.prototype-@@split
//
// NOTE: This cannot be properly polyfilled in engines that don't support
// the 'y' flag.
function (regexp, limit) {
var res = maybeCallNative(internalSplit, regexp, this, limit, internalSplit !== $split);
if (res.done) return res.value;
var rx = anObject(regexp);
var S = String(this);
var C = speciesConstructor(rx, RegExp);
var unicodeMatching = rx.unicode;
var flags = (rx.ignoreCase ? 'i' : '') +
(rx.multiline ? 'm' : '') +
(rx.unicode ? 'u' : '') +
(SUPPORTS_Y ? 'y' : 'g');
// ^(? + rx + ) is needed, in combination with some S slicing, to
// simulate the 'y' flag.
var splitter = new C(SUPPORTS_Y ? rx : '^(?:' + rx.source + ')', flags);
var lim = limit === undefined ? MAX_UINT32 : limit >>> 0;
if (lim === 0) return [];
if (S.length === 0) return callRegExpExec(splitter, S) === null ? [S] : [];
var p = 0;
var q = 0;
var A = [];
while (q < S.length) {
splitter.lastIndex = SUPPORTS_Y ? q : 0;
var z = callRegExpExec(splitter, SUPPORTS_Y ? S : S.slice(q));
var e;
if (
z === null ||
(e = $min(toLength(splitter.lastIndex + (SUPPORTS_Y ? 0 : q)), S.length)) === p
) {
q = advanceStringIndex(S, q, unicodeMatching);
} else {
A.push(S.slice(p, q));
if (A.length === lim) return A;
for (var i = 1; i <= z.length - 1; i++) {
A.push(z[i]);
if (A.length === lim) return A;
}
q = p = e;
}
}
A.push(S.slice(p));
return A;
}
];
});