Utilizing Callback Functions to Generate a 'Map' in a customized 'Each' Function - JavaScript

In my coding project, I am using a custom 'each()' function that iterates through a collection and performs a specific function on it.

_['each'] = function(collection, iterator) {
  if (Array.isArray(collection) === false && typeof(collection) === 
'object') {
    var values = Object.values(collection);
    var keys = Object.keys(collection);
    for (let i = 0; i < values.length; i++) {
      iterator(values[i], keys[i], collection, i);
    }    
  } else {
    for (let i = 0; i < collection.length; i++) {
      iterator(collection[i], i, collection);
    }
  }
}

Now, I am trying to create a new 'map()' function that will take the results of the operations performed by 'each()' and return a fresh array. However, I am facing difficulty in finding a way to access the values extracted during iterations when implementing 'map()'. Should I modify 'each()' to include an additional callback parameter for adding values to a collection?

Answer №1

To start, create a new array and use the _.each method on the given collection to populate the newly created array with the results. Here's an example:

_['transform'] = function(collection, func) {
   var output = [];

   var transformFunc = function(value, key, collection, index) {
      output[index] = func(value, key, collection, index);
   }

   _['each'](collection, transformFunc);
   return output;
}

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