spread operator ... code example

Example 1: array spread operator in javascript

let arr1 = ['A', 'B', 'C'];

let arr2 = ['X', 'Y', 'Z'];

let result = [...arr1, ...arr2];

console.log(result); // ['A', 'B', 'C', 'X', 'Y', 'Z']
// spread elements of the array instead of taking the array as a whole

Example 2: spread operator javascript

obj = {first_name : "Marty",
    lovers: ["Jennifer Parker","Baines McFly"]
      };
let objClone = { ...obj }; // pass all key:value pairs from an object 

console.log(objClone)
// { first_name: "Marty", lovers: ["Jennifer Parker", "Baines McFly"] }

Example 3: spread operator javascript

const parts = ['shoulders', 'knees']; 
const lyrics = ['head', ...parts, 'and', 'toes']; 
//  ["head", "shoulders", "knees", "and", "toes"]

Example 4: spread operator

function sum(x, y, z) {
  return x + y + z;
}

const numbers = [1, 2, 3];

console.log(sum(...numbers));
// expected output: 6
// This will add each item in number arrray in sum method.

console.log(sum.apply(null, numbers));
// expected output: 6