bit-bin/dist/utils/array/split-by.js

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"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.default = splitBy;

/**
 * splits an array to two chunks using a conditional predicate function.
 * @name splitBy
 * @param {[*]} array array to split.
 * @param {() => boolean} fn predicate function to test each element of the array.
 * @returns {[[], []]} two new arrays with the elements that failed the test from the left.
 * @example
 * ```js
 *  splitBy([1, 2, 3, 4, 5], isEven) // => [[1, 3, 5], [2, 4]]
 * ```
 */
function splitBy(array, fn) {
  const truthy = [];
  const falsy = [];
  array.forEach(elm => {
    if (fn(elm)) truthy.push(elm);else falsy.push(elm);
  });
  return [falsy, truthy];
}