How to get unique array with only filter in Javascript [duplicate]

Question

I have an array:

var a = [2,3,4,5,5,4]

I want to get unique array out of given array like

b = [2,3,4,5]

I have tried

a.filter(function(d){return b.indexOf(d)>-1})

and I don't want to use for loop.

Answer 1

This is not an Angular related problem. It can be resolved in a couple of ways depending which libraries you are using.

If you are using jquery:

var uniqeElements = $.unique([2,3,4,5,5,4]);

The output would be:

[2,3,4,5]

If you are using underscore:

var uniqeElements = _.uniq([2,3,4,5,5,4]);

Same output.

And pure JS code:

var unique = [2,3,4,5,5,4].filter(function(elem, index, self) {
    return index == self.indexOf(elem);
})

Answer 2

You can simply do it in JavaScript, with the help of the second - index - parameter of the filter method:

var a = [2,3,4,5,5,4];
a.filter(function(value, index){ return a.indexOf(value) == index });