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array_utils.js
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array_utils.js
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/*! @license
* Shaka Player
* Copyright 2016 Google LLC
* SPDX-License-Identifier: Apache-2.0
*/
goog.provide('shaka.util.ArrayUtils');
/**
* @namespace shaka.util.ArrayUtils
* @summary Array utility functions.
*/
shaka.util.ArrayUtils = class {
/**
* Returns whether the two values contain the same value. This correctly
* handles comparisons involving NaN.
* @param {T} a
* @param {T} b
* @return {boolean}
* @template T
*/
static defaultEquals(a, b) {
// NaN !== NaN, so we need to special case it.
if (typeof a === 'number' &&
typeof b === 'number' && isNaN(a) && isNaN(b)) {
return true;
}
return a === b;
}
/**
* Remove given element from array (assumes no duplicates).
* @param {!Array.<T>} array
* @param {T} element
* @template T
*/
static remove(array, element) {
const index = array.indexOf(element);
if (index > -1) {
array.splice(index, 1);
}
}
/**
* Count the number of items in the list that pass the check function.
* @param {!Array.<T>} array
* @param {function(T):boolean} check
* @return {number}
* @template T
*/
static count(array, check) {
let count = 0;
for (const element of array) {
count += check(element) ? 1 : 0;
}
return count;
}
/**
* Determines if the given arrays contain equal elements in any order.
*
* @param {!Array.<T>} a
* @param {!Array.<T>} b
* @param {function(T, T):boolean=} compareFn
* @return {boolean}
* @template T
*/
static hasSameElements(a, b, compareFn) {
if (!compareFn) {
compareFn = shaka.util.ArrayUtils.defaultEquals;
}
if (a.length != b.length) {
return false;
}
const copy = b.slice();
for (const item of a) {
const idx = copy.findIndex((other) => compareFn(item, other));
if (idx == -1) {
return false;
}
// Since order doesn't matter, just swap the last element with
// this one and then drop the last element.
copy[idx] = copy[copy.length - 1];
copy.pop();
}
return copy.length == 0;
}
/**
* Determines if the given arrays contain equal elements in the same order.
*
* @param {!Array.<T>} a
* @param {!Array.<T>} b
* @param {function(T, T):boolean=} compareFn
* @return {boolean}
* @template T
*/
static equal(a, b, compareFn) {
if (!compareFn) {
compareFn = shaka.util.ArrayUtils.defaultEquals;
}
if (a.length != b.length) {
return false;
}
for (let i = 0; i < a.length; i++) {
if (!compareFn(a[i], b[i])) {
return false;
}
}
return true;
}
};