using lodash unique on an array of arrays

Question

I am not sure how to use this to remove duplicate arrays from the main array. so consider the following:

var arr = [
    [0, 1],
    [0, 1],
    [2, 1],
];

The resulting array should look like:

var arr = [
    [0, 1],
    [2, 1],
];

The documentation makes sense for a single array of elements but not a 2d array.

Ideas?

Update, One small issue with some solutions:

The array to be turned unique might have:

var arr = [
  [0, 1]
  [0, 2]
  [0, 3]
  [0, 1]
  [2, 1]
]

the array in side the array should have all value compared, so in the above example, it should spit out:

var arr = [
  [0, 1]
  [0, 2]
  [0, 3]
  [2, 1]
]

The duplicate being [0, 1]

Answer 1

The easiest way would probably be to use uniq method and then convert the inner arrays to some string representation, JSON.stringify should be good enough solution.

var arr = [[0, 1], [0, 2], [0, 3], [0, 1], [2, 1]]
_.uniq(arr, function(item) { 
    return JSON.stringify(item); 
});
// [[0,1], [0,2], [0,3], [2,1]]