There are countless ways to iterate through JS objects and arrays. Here’s how to do it in the simplest way, with ES6 and beyond, for each purpose.

Objects

Keys and values

Loop through keys and values of an object.

Keys

Loop through keys of an object.

Values

Loop through values of an object.

Arrays

Loop through an array.

Return

If you want to return the items or the whole loop, you have to swap the forEach for a map. You can change it in any of the examples above, it will work as expected, and the result will be returned. A forEach will always return undefined.

Build a simple Node.js CLI tool without any dependencies. A single command to clone and install a repository.

Don’t make me install your CLI

Npm has a great command called init. Running the command npm init <something> temporarily installs a package you named create-<something> to run its main entry. It uses npx under the hood, but with a more familiar command.

One significant advantage of init is that it always uses the latest version of your package; you don’t have to update it manually as you would have to globally. But it still works, you can install the package globally if you prefer.

The package

To get started, you need a package.json file. By default, it uses the name field to run the main file in the terminal. To use a different name than the package name, set it in the bin field. …