Chaining method calls in JavaScript

In JavaScript sometimes we can chain method calls, like this:

car.start().drive()

It’s pretty convenient to do so.

Instead of writing

car.start()
car.drive()

we can simplify in a one-liner.

This is possible if each method returns the object itself. In other words, the implementation must be something like this:

const car = {
  start: function() {
    console.log('start')
    return this
  },
  drive: function() {
    console.log('drive')
    return this
  }
}

It’s important to note that you can’t use arrow functions, because this in an arrow function used as object method is not bound to the object instance.

I like to use arrow functions all the time, and this is one of the cases where you can’t.

Chained method calls are great when you are not returning a set of values from the method, otherwise you obviously need to assign a method call to a variable, and chaining is not possible:

const result = car.start()
if (result) {
  car.drive()
}