/* 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} a Array of values to be compared * @param {ArrayLike} 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} arr Array of values to be partitioned * @param {(value: T) => boolean} fn Partition function which partitions based on truthiness of result. * @returns {[Array, Array]} returns the values of `arr` partitioned into two new arrays based on fn predicate. */ exports.groupBy = (arr = [], fn) => { return arr.reduce( /** * @param {[Array, Array]} groups An accumulator storing already partitioned values returned from previous call. * @param {T} value The value of the current element * @returns {[Array, Array]} 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; }, [[], []] ); };