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34 lines
1010 B
34 lines
1010 B
'use strict'; |
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var GetIntrinsic = require('get-intrinsic'); |
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var CodePointAt = require('./CodePointAt'); |
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var IsIntegralNumber = require('./IsIntegralNumber'); |
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var Type = require('./Type'); |
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var MAX_SAFE_INTEGER = require('../helpers/maxSafeInteger'); |
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var $TypeError = GetIntrinsic('%TypeError%'); |
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// https://ecma-international.org/ecma-262/12.0/#sec-advancestringindex |
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module.exports = function AdvanceStringIndex(S, index, unicode) { |
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if (Type(S) !== 'String') { |
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throw new $TypeError('Assertion failed: `S` must be a String'); |
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} |
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if (!IsIntegralNumber(index) || index < 0 || index > MAX_SAFE_INTEGER) { |
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throw new $TypeError('Assertion failed: `length` must be an integer >= 0 and <= 2**53'); |
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} |
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if (Type(unicode) !== 'Boolean') { |
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throw new $TypeError('Assertion failed: `unicode` must be a Boolean'); |
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} |
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if (!unicode) { |
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return index + 1; |
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} |
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var length = S.length; |
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if ((index + 1) >= length) { |
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return index + 1; |
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} |
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var cp = CodePointAt(S, index); |
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return index + cp['[[CodeUnitCount]]']; |
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};
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