Vmeda.Online/src/core/singletons/array.ts

62 lines
1.7 KiB
TypeScript

// (C) Copyright 2015 Moodle Pty Ltd.
//
// 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.
/**
* Singleton with helper functions for arrays.
*/
export class CoreArray {
/**
* Check whether an array contains an item.
*
* @param arr Array.
* @param item Item.
* @return Whether item is within the array.
*/
static contains<T>(arr: T[], item: T): boolean {
return arr.indexOf(item) !== -1;
}
/**
* Flatten the first dimension of a multi-dimensional array.
*
* @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/flat#reduce_and_concat
*
* @param arr Original array.
* @return Flattened array.
*/
static flatten<T>(arr: T[][]): T[] {
return (<T[]> []).concat(...arr);
}
/**
* Obtain a new array without the specified item.
*
* @param arr Array.
* @param item Item to remove.
* @return Array without the specified item.
*/
static withoutItem<T>(arr: T[], item: T): T[] {
const newArray = [...arr];
const index = arr.indexOf(item);
if (index !== -1) {
newArray.splice(index, 1);
}
return newArray;
}
}