How to get only unique values of a 2d array - google-apps-script

Question

I need to get the following 2d array from:
[[Option 10, 2.0], [Option 10, 2.0], [Option 9, 1.0], [Option 7, 1.0]]
to
[[Option 10, 2.0], [Option 9, 1.0], [Option 7, 1.0]]
I found this post (Splitting a 2D array using some() , by date, avoiding duplicates. Just want 1 unique email, not row. Where am i wrong here?) that has a very efficient way of getting unique values, but I cannot figure out how to apply it to my situation.

Answer 1

Your use case is simpler than the one you refer to.
try this for example :
function myFunction() {
var source = [['Option 10', 2], ['Option 10', 2], ['Option 9', 1], ['Option 7', 1]];
var dest = [];
dest.push(source[0]);
for(var n = 1 ; n< source.length ; n++){
if(dest.join().indexOf(source[n].join()) == -1){dest.push(source[n])};
}
Logger.log(dest);
}

Answer 2

Because 'unique' is not always simple to describe, I often use a pattern which is is, in effect, a variation of Serge's correct answer using ES5 array map/filter functions.
An edited version:
function hash(arr) {
// in this case the hash method is the same as Serge's Array.join() method,
but could be customised to suit whatever condition you need to generate
bespoke comparators such as where `1 + 3` should match `2 + 2`, or where
particular columns in the array can be omitted
return arr.join();
}
function myFunction() {
var source = [['Option 10', 2], ['Option 10', 2], ['Option 9', 1], ['Option 7', 1]];
var hash = source.map(
function (row) {
return hash(row);
}
);
source = source.filter(
function (filterRow, i) {
return hash.slice(0, i).indexOf(hash(filterRow)) < 0;
}
);
Logger.log(source);
}
I only include this as there are times when your comparison may need to flex a little. In your example this isn't important which is why Serge's is correct, but I share to show a potential expansion food for thought for when unique needs to be 'tweaked'