35 lines
993 B
JavaScript
35 lines
993 B
JavaScript
'use strict';
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var GetIntrinsic = require('get-intrinsic');
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var CodePointAt = require('./CodePointAt');
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var Type = require('./Type');
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var isInteger = require('../helpers/isInteger');
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var MAX_SAFE_INTEGER = require('../helpers/maxSafeInteger');
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var $TypeError = GetIntrinsic('%TypeError%');
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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 (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 (!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 (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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