@bbashcode/lotide-flex/takeUntil.js

A clone of the lodash JavaScript library to practice creating various types of functions using JS.

/**
 * eqArrays method is used to compare two arrays for a perfect match
 * @param  {array} array1 The first param
 * @param  {array} array2 The second param
 * @return {boolean} returns true or false depending on whether both arrays are equal or not
 */
 const eqArrays = (array1, array2) =>
 array1.length === array2.length &&
 array1.every((element, index) => element === array2[index]);


 /**
 * assertArraysEqual method is used for asserting that two arrays are equal
 * @param  {array} actual The first param
 * @param  {array} expected The second param
 * @return {void/undefined} This method does not return anything, rather the side effect is to console log test pass or fail based on comparison
 */
const assertArraysEqual = function(actual, expected) {
  if (eqArrays(actual, expected)) {
    console.log(`✅✅✅ Assertion Passed: ${actual} === ${expected}`);
  } else {
    console.log(`🛑🛑🛑 Assertion Failed: ${actual} !== ${expected}`);
  }
};

/**
 * takeUntil is a methof that keeps collecting items from a provided array until the callback provided returns a truthy value.
 * @param  {array} array The first param is an array
 * @param  {function} callbacl The second param is a callback function
 * @return {void/undefined}  returns a shallow copy of the array that satisfies the callback condition
 */
const takeUntil = function(array, callback){
  let results = [];
  for(let item of array){
   if(!callback(item)){
      results.push(item);
    } else {
      break;
    }
  }
  return results;
};

//TEST CODE
const data1 = [1, 2, 5, 7, 2, -1, 2, 4, 5];
// const results1 = takeUntil(data1, x => x < 0);
// console.log(results1);

// console.log('---');

const data2 = ["I've", "been", "to", "Hollywood", ",", "I've", "been", "to", "Redwood"];
// const results2 = takeUntil(data2, x => x === ',');
// console.log(results2);

assertArraysEqual([ 1, 2, 5, 7, 2 ], takeUntil(data1, x => x < 0));
assertArraysEqual(takeUntil(data2, x => x === ','),[ 'I\'ve', 'been', 'to', 'Hollywood' ]);