How to remove duplicates from an array of objects?

Question

What the best way to remove duplicates from an array of objects?

var array = [
 {a: 0, b: 0, c: 0},
 {a: 0, b: 0, c: 0},
 {a: 1, b: 1, c: 1},
 {a: 1, b: 1, c: 1},
 //..... etc
];

And, i want to get like:

[
 {a: 0, b: 0, c: 0},
 {a: 1, b: 1, c: 1}
];

PS: the keys (a, b, c) have only primitive data type (String, Number)

Please, without underscore.js and other libs.

• Dancrumb: What happened to the cs?
• Dancrumb: Also, does order matter?
• Dancrumb: Finally... why not use underscore?
• Mike Samuel: What is your equality function? I.e. what does it mean for two objects to be duplicative of one another? Are you assuming no-one will mutate elements of this array?
• Robbin: @Dancrumb, I dont want to use the underscore.js in my project, because there're no any reasons for it

Answer 1

I'm sure there is better ways to do this, but you can use this prototype function.

Array.prototype.removeDuplicates = function () {
 var r = new Array();
 o:for(var i = 0, n = this.length; i < n; i++)
 {
 for(var x = 0, y = r.length; x < y; x++)
 if(r[x].a==this[i].a && r[x].b==this[i].b && r[x].c==this[i].c)
 continue o;
 r.push(this[i]);
 }
 return r;
}

How to use it

var arr = [
 {a: 0, b: 0, c: 0},
 {a: 0, b: 0, c: 0},
 {a: 1, b: 1, c: 1},
 {a: 1, b: 1, c: 1},
 //..... etc
];
var uniques = arr.removeDuplicates();
console.log(uniques);

Note:

You should avoid this for big arrays, out there are better solutions

• Robbin: Could you rewrite your example without o: ?
• Tomas Ramirez Sarduy: @Robbin: I think a better idea is that you rewrite the code. Hint: use a bit (value 0 or 1) inside loop
• Lion789: How big of arrays should be avoided, and I have been looking, anyone have a link or can state a better solution, I have the same issue but have arrays with a couple thousand objects to go through...
• Tomas Ramirez Sarduy: @Lion789: In that case you need to study algorithms for that and maybe some heuristics
• Lion789: Ok, by the way, using the above prototype, how would you go about removing duplicates and merging two or more arrays?