lodash map

Understanding Lodash Map

If you are a JavaScript developer, you must be aware of the popular JavaScript utility library called Lodash. It is a collection of methods that makes the task of working with arrays, numbers, objects, and strings simpler and more efficient.

Lodash map is one of the most commonly used methods from the library. It is used to iterate over an array or object, apply a function to each element, and return a new array of the results. The syntax for using the method is as follows:

_.map(collection, [iteratee=_.identity])

The collection parameter is the array or object that needs to be traversed, and iteratee is the function that will be applied to each element.

Example Usage

Let's consider an example where we have an array of numbers and we want to square each number using the Lodash map method. Here's how we can do it:

const numbers = [1, 2, 3, 4, 5];

const squaredNumbers = _.map(numbers, (num) => num * num);

console.log(squaredNumbers); // Output: [1, 4, 9, 16, 25]

In the above example, we first define an array of numbers. Then we pass this array as the first argument to the Lodash map method. We also define a function as the second argument that takes each number as input, squares it, and returns the result. The method then applies this function to each element of the array and returns a new array of squared numbers.

Multiple Ways to Use Lodash Map

There are multiple ways you can use the Lodash map method. Here are some examples:

  • You can pass an object as the first argument instead of an array. In this case, the method will iterate over the object keys instead of array indices.
  • You can pass an additional argument to the iteratee function that represents the index of the current element in the collection.
  • You can use the shorthand syntax instead of defining a function for the iteratee parameter. For example, instead of writing (num) => num * num, you can write '*' as a shorthand for the multiplication operation.


Lodash map is a powerful method that makes it easy to iterate over arrays and objects, apply a function to each element, and return a new array. By using this method, you can simplify your code and make it more efficient.

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