1 | 'use strict';
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2 | var uncurryThis = require('../internals/function-uncurry-this');
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3 | var hasOwn = require('../internals/has-own-property');
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4 |
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5 | var $SyntaxError = SyntaxError;
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6 | var $parseInt = parseInt;
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7 | var fromCharCode = String.fromCharCode;
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8 | var at = uncurryThis(''.charAt);
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9 | var slice = uncurryThis(''.slice);
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10 | var exec = uncurryThis(/./.exec);
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11 |
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12 | var codePoints = {
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13 | '\\"': '"',
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14 | '\\\\': '\\',
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15 | '\\/': '/',
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16 | '\\b': '\b',
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17 | '\\f': '\f',
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18 | '\\n': '\n',
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19 | '\\r': '\r',
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20 | '\\t': '\t'
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21 | };
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22 |
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23 | var IS_4_HEX_DIGITS = /^[\da-f]{4}$/i;
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24 |
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25 | var IS_C0_CONTROL_CODE = /^[\u0000-\u001F]$/;
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26 |
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27 | module.exports = function (source, i) {
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28 | var unterminated = true;
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29 | var value = '';
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30 | while (i < source.length) {
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31 | var chr = at(source, i);
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32 | if (chr === '\\') {
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33 | var twoChars = slice(source, i, i + 2);
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34 | if (hasOwn(codePoints, twoChars)) {
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35 | value += codePoints[twoChars];
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36 | i += 2;
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37 | } else if (twoChars === '\\u') {
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38 | i += 2;
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39 | var fourHexDigits = slice(source, i, i + 4);
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40 | if (!exec(IS_4_HEX_DIGITS, fourHexDigits)) throw new $SyntaxError('Bad Unicode escape at: ' + i);
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41 | value += fromCharCode($parseInt(fourHexDigits, 16));
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42 | i += 4;
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43 | } else throw new $SyntaxError('Unknown escape sequence: "' + twoChars + '"');
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44 | } else if (chr === '"') {
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45 | unterminated = false;
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46 | i++;
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47 | break;
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48 | } else {
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49 | if (exec(IS_C0_CONTROL_CODE, chr)) throw new $SyntaxError('Bad control character in string literal at: ' + i);
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50 | value += chr;
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51 | i++;
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52 | }
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53 | }
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54 | if (unterminated) throw new $SyntaxError('Unterminated string at: ' + i);
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55 | return { value: value, end: i };
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56 | };
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