takeUntil.js

const assertArraysEqual = require("./assertArraysEqual");
//parameter 'array' takes arrays, 'callback' takes callback function 
//if the callback function returns a truthy value when invoked with the current item,
//it immediately return result array and finishes loop.
//otherwise the current item is added into result array
const takeUntil = function(array, callback) {
  const result = [];
  for (const item of array) {
    
    if(callback(item)) {
      return result;
    } else {
      result.push(item);
    }
  } return result;
}

/*
callback = function(x) {
  x === ","
}
*/

// //TEST CODE
// const data1 = [1, 2, 5, 7, 2, -1, 2, 4, 5];
// const expected1 = [1, 2, 5, 7, 2];
// const results1 = takeUntil(data1, x => x < 0);
// console.log(results1);

// assertArraysEqual(expected1, results1);

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

// const data2 = ["I've", "been", "to", "Hollywood", ",", "I've", "been", "to", "Redwood"];
// const expected2 = [ 'I\'ve', 'been', 'to', 'Hollywood' ]
// const results2 = takeUntil(data2, x => x === ',');
// console.log(results2);
// assertArraysEqual(expected2, results2);

module.exports = takeUntil;