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esnext.regexp.escape.js
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esnext.regexp.escape.js
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'use strict';
var $ = require('../internals/export');
var uncurryThis = require('../internals/function-uncurry-this');
var aString = require('../internals/a-string');
var padStart = require('../internals/string-pad').start;
var WHITESPACES = require('../internals/whitespaces');
var $Array = Array;
var charAt = uncurryThis(''.charAt);
var charCodeAt = uncurryThis(''.charCodeAt);
var numberToString = uncurryThis(1.1.toString);
var join = uncurryThis([].join);
var FIRST_DIGIT_OR_ASCII = /^[0-9a-z]/i;
var SYNTAX_SOLIDUS_AND_CONTROL = /^[\t\n\v\f\r$()*+./?[\\\]^{|}]/;
var OTHER_PUNCTUATORS_AND_WHITESPACES = RegExp('^[!"#%&\',\\-:;<=>@`~' + WHITESPACES + ']');
var exec = uncurryThis(FIRST_DIGIT_OR_ASCII.exec);
var escapeChar = function (chr) {
var hex = numberToString(charCodeAt(chr, 0), 16);
return hex.length < 3 ? '\\x' + padStart(hex, 2, '0') : '\\u' + padStart(hex, 4, '0');
};
// `RegExp.escape` method
// https://github.com/tc39/proposal-regex-escaping
$({ target: 'RegExp', stat: true, forced: true }, {
escape: function escape(S) {
aString(S);
var length = S.length;
var result = $Array(length);
for (var i = 0; i < length; i++) {
var chr = charAt(S, i);
if (i === 0 && exec(FIRST_DIGIT_OR_ASCII, chr)) {
result[i] = escapeChar(chr);
} else if (exec(SYNTAX_SOLIDUS_AND_CONTROL, chr)) {
result[i] = '\\' + chr;
} else if (exec(OTHER_PUNCTUATORS_AND_WHITESPACES, chr)) {
result[i] = escapeChar(chr);
} else {
var charCode = charCodeAt(chr, 0);
// single UTF-16 code unit
if ((charCode & 0xF800) !== 0xD800) result[i] = chr;
// unpaired surrogate
else if (charCode >= 0xDC00 || i + 1 >= length || (charCodeAt(S, i + 1) & 0xFC00) !== 0xDC00) result[i] = escapeChar(chr);
// surrogate pair
else {
result[i] = chr;
result[++i] = charAt(S, i);
}
}
}
return join(result, '');
}
});