Given an array: const myArr = [1, 2, 3, 4, 1, 1, 4], how to remove duplicates?
We can take advantage of Set - it's a built-in function constructor in JS.
const mySet = new Set(myArr)
This solves our immediate issue of removing the duplicates; now, to just turn this back into an array.
const myNewArr = [...mySet]
We have taken mySet 👆🏽 and spread it out with .... Then, we have just wrapped up these 'loose elements' into a new array as we see from the presence of [].
And, putting it all together, we can create a 'one-line utility function:' const removeDuplicates = (a) => [...new Set(a)]
You can see some other of the utility functions I routinely use here.
Top comments (4)
Cool haven't thought of using "Set" yet. You could also filter directly on the array:
const unique = myArr.filter((value, index, array) => array.indexOf(value) === index);
That is significantly slower though, the Set uses an O(1) lookup so the routine is O(N) whereas indexOf would make it O(N**2)
Nice to know. Will try that next time.
It is working in this case, those objects are each unique. It isn't working by comparing the contents of the object for sure.