The Spread Operator in JavaScript simply copies all the elements of an array and outputs them to the console. It is represented by … i.e., the three dots.

Let’s understand it better using the simple code below:

const animals1 = ['cat','dog','tiger'];
const animals2 = ['lion','giraffe','hippo'];
const allAnimals = [ ...animals1, ...animals2];
console.log(allAnimals);

// returns ['cat', 'dog', 'tiger', 'lion', 'giraffe', 'hippo']
 

The spread Operator has been around since JavaScript ES6. It helps in extracting properties from old objects or arrays to new ones.

Here’s a function which uses the Spread Operator :

function makeThingsEasy() {
     let line1 = ['how', 'are' , 'you' ,'doing'];
     let line2 = ['Hello!', ...line1, 'today'];
     return line2;
}

makeThingsEasy(); 

// outputs ['Hello!', 'how', 'are', 'you', 'doing', 'today']