57 lines
1.6 KiB
JavaScript
57 lines
1.6 KiB
JavaScript
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'use strict';
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var uncurryThis = require('../internals/function-uncurry-this');
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var hasOwn = require('../internals/has-own-property');
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var $SyntaxError = SyntaxError;
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var $parseInt = parseInt;
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var fromCharCode = String.fromCharCode;
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var at = uncurryThis(''.charAt);
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var slice = uncurryThis(''.slice);
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var exec = uncurryThis(/./.exec);
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var codePoints = {
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'\\"': '"',
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'\\\\': '\\',
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'\\/': '/',
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'\\b': '\b',
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'\\f': '\f',
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'\\n': '\n',
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'\\r': '\r',
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'\\t': '\t'
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};
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var IS_4_HEX_DIGITS = /^[\da-f]{4}$/i;
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// eslint-disable-next-line regexp/no-control-character -- safe
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var IS_C0_CONTROL_CODE = /^[\u0000-\u001F]$/;
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module.exports = function (source, i) {
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var unterminated = true;
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var value = '';
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while (i < source.length) {
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var chr = at(source, i);
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if (chr === '\\') {
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var twoChars = slice(source, i, i + 2);
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if (hasOwn(codePoints, twoChars)) {
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value += codePoints[twoChars];
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i += 2;
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} else if (twoChars === '\\u') {
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i += 2;
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var fourHexDigits = slice(source, i, i + 4);
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if (!exec(IS_4_HEX_DIGITS, fourHexDigits)) throw new $SyntaxError('Bad Unicode escape at: ' + i);
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value += fromCharCode($parseInt(fourHexDigits, 16));
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i += 4;
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} else throw new $SyntaxError('Unknown escape sequence: "' + twoChars + '"');
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} else if (chr === '"') {
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unterminated = false;
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i++;
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break;
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} else {
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if (exec(IS_C0_CONTROL_CODE, chr)) throw new $SyntaxError('Bad control character in string literal at: ' + i);
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value += chr;
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i++;
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}
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}
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if (unterminated) throw new $SyntaxError('Unterminated string at: ' + i);
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return { value: value, end: i };
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};
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