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