Ways to remove duplicates in JS

We will see what all ways can we remove duplicates from an array, starting off with the most obvious approach and gradually moving towards different ways.

You have

const arr = [1,2,4,3,1,1,4]

1. The not so elegant way

And you want to remove the duplicates. The most basic approach will be

let final = [];

for(let i of arr) {
	if(final.indexOf(i) === -1){
    	final.push(i);
    }
}

2. Using map

You can always replace the iteration with map. But this does not change much.

let final = [];

arr.map((c) => {
    if(final.indexOf(c) === -1) {
        final.push(c);
    }
})

3. Using filter

Using filter does make things look a little clean.

let final = arr.filter((cur,index) => arr.indexOf(cur) == index)

4. Using set

But nothing beats a set.

let final = [...new Set(arr)]