Constnium/node_modules/es-abstract/2021/StringIndexOf.js
2022-06-23 02:27:43 +02:00

39 lines
1.1 KiB
JavaScript

'use strict';
var GetIntrinsic = require('get-intrinsic');
var callBound = require('call-bind/callBound');
var $TypeError = GetIntrinsic('%TypeError%');
var IsIntegralNumber = require('./IsIntegralNumber');
var Type = require('./Type');
var $slice = callBound('String.prototype.slice');
// https://ecma-international.org/ecma-262/12.0/#sec-stringindexof
module.exports = function StringIndexOf(string, searchValue, fromIndex) {
if (Type(string) !== 'String') {
throw new $TypeError('Assertion failed: `string` must be a String');
}
if (Type(searchValue) !== 'String') {
throw new $TypeError('Assertion failed: `searchValue` must be a String');
}
if (!IsIntegralNumber(fromIndex) || fromIndex < 0) {
throw new $TypeError('Assertion failed: `fromIndex` must be a non-negative integer');
}
var len = string.length;
if (searchValue === '' && fromIndex <= len) {
return fromIndex;
}
var searchLen = searchValue.length;
for (var i = fromIndex; i <= (len - searchLen); i += 1) {
var candidate = $slice(string, i, i + searchLen);
if (candidate === searchValue) {
return i;
}
}
return -1;
};