/** * @license Copyright (c) 2003-2020, CKSource - Frederico Knabben. All rights reserved. * For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-oss-license */ import first from '../src/first'; describe( 'utils', () => { describe( 'first', () => { it( 'should return first item', () => { const collection = [ 11, 22 ]; const iterator = collection[ Symbol.iterator ](); expect( first( iterator ) ).to.equal( 11 ); } ); it( 'should return null if iterator is empty', () => { const collection = []; const iterator = collection[ Symbol.iterator ](); expect( first( iterator ) ).to.be.null; } ); it( 'should consume the iterating item', () => { const collection = [ 11, 22 ]; const iterator = collection[ Symbol.iterator ](); first( iterator ); expect( iterator.next().value ).to.equal( 22 ); } ); } ); } );