What is ... in Javascript?
It is called the spread operator and used to add old data to a new file as below example.
const newArr = [...oldArr,1,2];
So it adds oldArr elements and 1 and 2 to the newArr.
This is also used if you want to copy the real value of an object instead of reference.
This is also used if you want to copy the real value of an object instead of reference.
What is destructuring in javascript?
Destructuring is a way of accessing elements from an object or an array as below.
const arr = {1,2,3};
[num1, num3] = numbers;
console.log(num1,num3);//This will print 1 and 2.
What does Javascript Map method do?
The map method returns a new array with result by using all elements of the existing array as below.
const arr = [1, 2,3];
// pass a function to map
const map = arr.map(x => x * 2);
console.log(map1);
// expected output: Array [2,4,6]
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