map.js

const words = ["home", "Matt", "bye", "glasses", "tom"];

const map = function(array, callback) {
  const results = [];
  for (let item of array) {
    results.push(callback(item));
  }
  return results;
}

const results1 = map(words, word => word[0]);

let eqArrays = (array1, array2) => {
  if (array1.length !== array2.length) {
    return false;
  }
  for (let i = 0; i < array1.length; i++) {
    if (array1[i] !== array2[i]) {
      return false;
    }
  }
  return true;
};

const assertArraysEqual = function (actual, expected) {
  if (eqArrays(actual, expected)) {
    console.log(`assertion passed`);
  } else {
    console.log(`🛑 ${actual} !== ${expected}`);
  }
};

assertArraysEqual(results1, [ 'h', 'M', 'b', 'g', 't' ]);
assertArraysEqual(results1, [ 'h', 'M', 'b', 'g']);
assertArraysEqual(results1, [ ]);

module.exports = map;