Method chaining in javascript

#javascript #codenewbie #oop #beginners

Method is a function that is a property of an object. It is also a property containing a function definition.
let's consider the example below

Var car = {
Color: “red”,
brand: “Toyota”,
description: function (){
This.brand  + "is a  Motor Corporation is a Japanese multinational automotive manufacturer"
}
}

// description is a property of a car that is also a function. So a function inside an object is called METHOD.
 //Calling 
console.log(car.description())
// Toyota is a  Motor Corporation is a Japanese multinational automotive manufacturer

If we have 5 methods in the object. We end up with something like this:
car.description()
car.description()
car.description()
car.description()
car.description()

Could you see that car is unnecessarily repeated and doesn’t seems neat and could take lines of code? We can get rid of that by using a mechanism called METHOD CHAINING.

Method chaining is the mechanism of calling a method on another method of the same object. This ensures a cleaner and readable code. Method chaining uses this keyword in the object's class to access its methods. In javascript, the this keyword refers to the current object in which it is called. When a method returns this, it simply returns an instance of the object in which it is returned. in another word, to chain methods together, we need to make sure that each method we define has a return value so that we can call another method on it.

Let's write some code

Class chaining{
    Method1(){
    console.log(method1)
    return this
    }

    Method2(){
    console.log(method2)
    return this
    }

}

 Const chaining_obj = new chaining()
 chaining_obj
 .mathod1()
 .method2()

//output
method1
method2

let's consider this example

class Arithmetic {
  constructor() {
    this.value = 0;
  }
  sum(...args) {
    this.value = args.reduce((sum, current) => sum + current, 0);
    return this;
  }
  addition(value) {
    this.value = this.value + value;
    return this;
  }
  subtraction(value) {
    this.value = this.value - value;
    return this;
  }
  average(...args) {
    this.value = args.length? (this.sum(...args).value) / 
  args.length: undefined;
    return this;
  }
}


const Arithmetic 1= new Arithmetic()
Arithmetic1
  .sum(1, 3, 6)   // => { value: 10 } 
  .subtraction(3)   // => { value: 7 }
  .add(4)        // => { value: 11 }
  .value         // => 11

Thanks for reading
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ISIAKA ABDULAHI

Top comments (8)

Abid Ramay • May 8 '22 • Edited

small typo, Arithmetic1.subtract(3) should be Arithmetic1.subtraction(3). There's no class method subtract().

ISIAKA ABDULAHI AKINKUNMI • Dec 4 '22

Thanks, that's true

Ina • Oct 28 '22

It will be nice to append add() method too and fix small typo:
const Arithmetic 1= new Arithmetic() into const Arithmetic1 = new Arithmetic()
Thanks!