44 lines
1.4 KiB
JavaScript
Executable file
44 lines
1.4 KiB
JavaScript
Executable file
/*
|
|
MIT License http://www.opensource.org/licenses/mit-license.php
|
|
Author Tobias Koppers @sokra
|
|
*/
|
|
|
|
"use strict";
|
|
|
|
/**
|
|
* Compare two arrays or strings by performing strict equality check for each value.
|
|
* @template T [T=any]
|
|
* @param {ArrayLike<T>} a Array of values to be compared
|
|
* @param {ArrayLike<T>} b Array of values to be compared
|
|
* @returns {boolean} returns true if all the elements of passed arrays are strictly equal.
|
|
*/
|
|
|
|
exports.equals = (a, b) => {
|
|
if (a.length !== b.length) return false;
|
|
for (let i = 0; i < a.length; i++) {
|
|
if (a[i] !== b[i]) return false;
|
|
}
|
|
return true;
|
|
};
|
|
|
|
/**
|
|
* Partition an array by calling a predicate function on each value.
|
|
* @template T [T=any]
|
|
* @param {Array<T>} arr Array of values to be partitioned
|
|
* @param {(value: T) => boolean} fn Partition function which partitions based on truthiness of result.
|
|
* @returns {[Array<T>, Array<T>]} returns the values of `arr` partitioned into two new arrays based on fn predicate.
|
|
*/
|
|
exports.groupBy = (arr = [], fn) => {
|
|
return arr.reduce(
|
|
/**
|
|
* @param {[Array<T>, Array<T>]} groups An accumulator storing already partitioned values returned from previous call.
|
|
* @param {T} value The value of the current element
|
|
* @returns {[Array<T>, Array<T>]} returns an array of partitioned groups accumulator resulting from calling a predicate on the current value.
|
|
*/
|
|
(groups, value) => {
|
|
groups[fn(value) ? 0 : 1].push(value);
|
|
return groups;
|
|
},
|
|
[[], []]
|
|
);
|
|
};
|