source: frontend/node_modules/es-abstract/2025/StringLastIndexOf.js

'use strict';

var $TypeError = require('es-errors/type');

var substring = require('./substring');

var isInteger = require('../helpers/isInteger');

// https://262.ecma-international.org/16.0/#sec-stringlastindexof

module.exports = function StringLastIndexOf(string, searchValue, fromIndex) {
        if (typeof string !== 'string') {
                throw new $TypeError('Assertion failed: `string` must be a string');
        }
        if (typeof searchValue !== 'string') {
                throw new $TypeError('Assertion failed: `searchValue` must be a string');
        }
        if (!isInteger(fromIndex) || fromIndex < 0) {
                throw new $TypeError('Assertion failed: `fromIndex` must be a non-negative integer');
        }

        var len = string.length; // step 1

        var searchLen = searchValue.length; // step 2

        if (!((fromIndex + searchLen) <= len)) {
                throw new $TypeError('Assertion failed: fromIndex + searchLen ≤ len'); // step 3
        }

        for (var i = fromIndex; i >= 0; i--) { // step 4
                var candidate = substring(string, i, i + searchLen); // step 4.a
                if (candidate === searchValue) {
                        return i; // step 4.b
                }
        }

        return 'NOT-FOUND'; // step 5
};