Javascript: Compare three arrays

Question

I want to compare many arrays and combine any that are identical:

A = [1,2,3];
B = [1,2,3];
C = [1,2,3];

D = [10,11,12];
E = [10,11,12];
F = [10,11,12];

G = [13,14];
H = [13,14];

If there are identical arrays then I'd like to create new arrays out of the identical ones:

I = [1,2,3];
J = [10,11,12];
K = [13,14];

Would I need to iterate through each element in one array against ALL of the elements in the other arrays?

for (var i in A) {
    for (var j in B) {
        if (A[i] == J[j]) {
            // create new arrays
        }
    }
}

etc...

Then, create new arrays out of the matches? Sounds like a lot of overhead.

What's the best way to accomplish this?

Thanks!

Answer 1

If you're just trying to finish up with the unique arrays, I would use a hash approach:

var myArrays = [A,B,C,D,E,F,G],
    uniques = [],
    hashes = {};

for (var i=0; i < myArrays.length; i++) {
    var hash = JSON.stringify(myArrays[i]); // or .toString(), or whatever
    if (!(hash in hashes)) {
        hashes[hash] = true;
        uniques.push(myArrays[i]);
    }
}
// uniques now holds all unique arrays