'use strict'; var $TypeError = require('es-errors/type'); var Call = require('es-abstract/2023/Call'); var CompletionRecord = require('es-abstract/2023/CompletionRecord'); var CreateIteratorFromClosure = require('../aos/CreateIteratorFromClosure'); var GetIteratorDirect = require('../aos/GetIteratorDirect'); var IsCallable = require('es-abstract/2023/IsCallable'); var IteratorClose = require('../aos/IteratorClose'); var IteratorStepValue = require('../aos/IteratorStepValue'); var ThrowCompletion = require('es-abstract/2023/ThrowCompletion'); var ToBoolean = require('es-abstract/2023/ToBoolean'); var Type = require('es-abstract/2023/Type'); var iterHelperProto = require('../IteratorHelperPrototype'); var SLOT = require('internal-slot'); module.exports = function filter(predicate) { if (this instanceof filter) { throw new $TypeError('`filter` is not a constructor'); } var O = this; // step 1 if (Type(O) !== 'Object') { throw new $TypeError('`this` value must be an Object'); // step 2 } if (!IsCallable(predicate)) { throw new $TypeError('`predicate` must be a function'); // step 3 } var iterated = GetIteratorDirect(O); // step 4 var closeIfAbrupt = function (abruptCompletion) { if (!(abruptCompletion instanceof CompletionRecord)) { throw new $TypeError('`abruptCompletion` must be a Completion Record'); } IteratorClose( iterated, abruptCompletion ); }; var sentinel = {}; var counter = 0; // step 6.a var closure = function () { // eslint-disable-next-line no-constant-condition while (true) { // step 6.b var value = IteratorStepValue(iterated); // step 6.b.i if (iterated['[[Done]]']) { return sentinel; // step 6.b.ii } var selected; try { selected = Call(predicate, void undefined, [value, counter]); // step 6.b.iv // yield mapped // step 6.b.vi if (ToBoolean(selected)) { return value; } } catch (e) { // close iterator // step 6.b.v, 6.b.vii closeIfAbrupt(ThrowCompletion(e)); throw e; } finally { counter += 1; // step 6.b.viii } } }; SLOT.set(closure, '[[Sentinel]]', sentinel); // for the userland implementation SLOT.set(closure, '[[CloseIfAbrupt]]', closeIfAbrupt); // for the userland implementation var result = CreateIteratorFromClosure(closure, 'Iterator Helper', iterHelperProto, ['[[UnderlyingIterator]]']); // step 7 SLOT.set(result, '[[UnderlyingIterator]]', iterated); // step 8 return result; // step 9 };