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30 lines
936 B
30 lines
936 B
'use strict'; |
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var CodePointAt = require('./CodePointAt'); |
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var $TypeError = require('es-errors/type'); |
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var isInteger = require('math-intrinsics/isInteger'); |
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var MAX_SAFE_INTEGER = require('math-intrinsics/constants/maxSafeInteger'); |
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// https://262.ecma-international.org/12.0/#sec-advancestringindex |
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module.exports = function AdvanceStringIndex(S, index, unicode) { |
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if (typeof 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 (!isInteger(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 (typeof 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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