javascript - Using lodash to compare jagged arrays (items existence without order)

Question

I know I can do it using loops, but I'm trying to find an elegant way of doing this:

I have two jagged arrays (array of arrays):

var array1 = [['a', 'b'], ['b', 'c']];
var array2 = [['b', 'c'], ['a', 'b']];

I want to use lodash to confirm that the above two jagged arrays are the same. By 'the same' I mean that there is no item in array1 that is not contained in array2. Notice that the items in jagged array are actually arrays. So I want to compare between inner arrays.

In terms of checking equality between these items:

['a', 'b'] == ['b', 'a'] 

or

['a', 'b'] == ['a', 'b'] 

Both work since the letters will always be in order.

---

UPDATE: Original question was talking about to "arrays" (instead of jagged arrays) and for years many people discussed (and added answers) about comparing simple one-dimensional arrays (without noticing that the examples provided in the question were not actually similar to the simple one-dimensional arrays they were expecting).

Answer 1

If you sort the outer array, you can use _.isEqual() since the inner array is already sorted.

var array1 = [['a', 'b'], ['b', 'c']];
var array2 = [['b', 'c'], ['a', 'b']];
_.isEqual(array1.sort(), array2.sort()); //true

Note that .sort() will mutate the arrays. If that's a problem for you, make a copy first using (for example) .slice() or the spread operator (...).

Or, do as Daniel Budick recommends in a comment below:

_.isEqual(_.sortBy(array1), _.sortBy(array2))

Lodash's sortBy() will not mutate the array.