@stdlib/iter/cuany-by/docs/types/test.ts

Standard iterator utilities.

/*
* @license Apache-2.0
*
* Copyright (c) 2024 The Stdlib Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
*    http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/

import { TypedIterator, TypedIteratorResult } from '@stdlib/types/iter';
import iterCuAnyBy = require( './index' );

/**
* Implements the iterator protocol `next` method.
*
* @returns iterator protocol-compliant object
*/
function next(): TypedIteratorResult<number> {
	return {
		'value': 2.0,
		'done': false
	};
}

/**
* Returns an iterator protocol-compliant object.
*
* @returns iterator protocol-compliant object
*/
function iterator(): TypedIterator<number> {
	return {
		'next': next
	};
}

/**
* Predicate function.
*
* @param _v - iterated value
* @param i - iteration index
* @returns a boolean
*/
function predicate1( _v: any, i: number ): boolean {
	return ( i > 10 );
}

/**
* Predicate function.
*
* @param v - iterated value
* @returns a boolean
*/
function predicate2( v: any ): boolean {
	return ( v !== v );
}


// TESTS //

// The function returns an iterator...
{
	iterCuAnyBy( iterator(), predicate1 ); // $ExpectType Iterator<boolean>
	iterCuAnyBy( iterator(), predicate2 ); // $ExpectType Iterator<boolean>
	iterCuAnyBy( iterator(), predicate1, {} ); // $ExpectType Iterator<boolean>
	iterCuAnyBy( iterator(), predicate2, {} ); // $ExpectType Iterator<boolean>
	iterCuAnyBy( iterator(), predicate1, null ); // $ExpectType Iterator<boolean>
	iterCuAnyBy( iterator(), predicate2, null ); // $ExpectType Iterator<boolean>
}

// The compiler throws an error if the function is provided a first argument which is not an iterator protocol-compliant object...
{
	iterCuAnyBy( '5', predicate1 ); // $ExpectError
	iterCuAnyBy( 5, predicate1 ); // $ExpectError
	iterCuAnyBy( true, predicate1 ); // $ExpectError
	iterCuAnyBy( false, predicate1 ); // $ExpectError
	iterCuAnyBy( null, predicate1 ); // $ExpectError
	iterCuAnyBy( undefined, predicate1 ); // $ExpectError
	iterCuAnyBy( [], predicate1 ); // $ExpectError
	iterCuAnyBy( {}, predicate1 ); // $ExpectError
	iterCuAnyBy( ( x: number ): number => x, predicate1 ); // $ExpectError
}

// The compiler throws an error if the function is provided a second argument which is not a predicate function...
{
	iterCuAnyBy( iterator(), '5' ); // $ExpectError
	iterCuAnyBy( iterator(), 5 ); // $ExpectError
	iterCuAnyBy( iterator(), true ); // $ExpectError
	iterCuAnyBy( iterator(), false ); // $ExpectError
	iterCuAnyBy( iterator(), null ); // $ExpectError
	iterCuAnyBy( iterator(), undefined ); // $ExpectError
	iterCuAnyBy( iterator(), [] ); // $ExpectError
	iterCuAnyBy( iterator(), {} ); // $ExpectError
	iterCuAnyBy( iterator(), ( x: number ): number => x ); // $ExpectError
}

// The compiler throws an error if the function is provided insufficient arguments...
{
	iterCuAnyBy(); // $ExpectError
	iterCuAnyBy( iterator() ); // $ExpectError
}