JS Interview Question/Ans Series

The interview question series continues …

6. Tell the key points of arrow function?

Ans: Arrow function is less verbose as we have to write less code.

let test = ()=> {  //syntax
  //statements
} 

We can write IIFE with arrow function. Function will be called immediately

(() => {
   //statements
})();

this here refers to global environment in arrow function. The reference of this is not the function itself but rather the window.

let test = ()=> { 
  console.log(this);
}
test();  // window object

In case of object literal with arrow function, this object doesn’t behave the way as in traditional function.

const obj = {
  test() {
    console.log(this); 
 }
}
obj.test();  //{test: f}  
const obj = {
  test:()=> {
    console.log(this); 
 }
}
obj.test();  //window object

The arrow function, doesn’t define arguments i.e. they do not have arguments binding.

// Object with Arrow function
let showData = {
    showArg: ()=>console.log(arguments);
}
showData.showArg(1,2,3); 
// Uncaught ReferenceError: arguments is not defined

But you can easily access the arrow function arguments using a rest parameter ...args.

// using rest parameters
let showData = {
    showArg: (...args)=>console.log(args);
}
myFunc.showArgs(1, 2, 3, 4); // [1, 2, 3, 4]

Thanks for Reading. For more information click on the below link.

Difference Between Arrow Function and Regular Function