FindViaPredicate.jsā¢1.42 kB
'use strict';
var $TypeError = require('es-errors/type');
var isInteger = require('math-intrinsics/isInteger');
var isObject = require('es-object-atoms/isObject');
var Call = require('./Call');
var Get = require('./Get');
var ToBoolean = require('./ToBoolean');
var IsCallable = require('./IsCallable');
var ToString = require('./ToString');
// https://262.ecma-international.org/14.0/#sec-findviapredicate
module.exports = function FindViaPredicate(O, len, direction, predicate, thisArg) {
if (!isObject(O)) {
throw new $TypeError('Assertion failed: Type(O) is not Object');
}
if (!isInteger(len) || len < 0) {
throw new $TypeError('Assertion failed: len must be a non-negative integer');
}
if (direction !== 'ascending' && direction !== 'descending') {
throw new $TypeError('Assertion failed: direction must be "ascending" or "descending"');
}
if (!IsCallable(predicate)) {
throw new $TypeError('predicate must be callable'); // step 1
}
for ( // steps 2-4
var k = direction === 'ascending' ? 0 : len - 1;
direction === 'ascending' ? k < len : k >= 0;
k += 1
) {
var Pk = ToString(k); // step 4.a
var kValue = Get(O, Pk); // step 4.c
var testResult = Call(predicate, thisArg, [kValue, k, O]); // step 4.d
if (ToBoolean(testResult)) {
return { '[[Index]]': k, '[[Value]]': kValue }; // step 4.e
}
}
return { '[[Index]]': -1, '[[Value]]': void undefined }; // step 5
};