How to filter out common array in array of arrays

Question

I have an array of arrays:

[
  [
    "Serta",
    "Black Friday"
  ],
  [
    "Serta",
    "Black Friday"
  ],
  [
    "Simmons",
    "Black Friday"
  ],
  [
    "Simmons",
    "Black Friday"
  ],
  [
    "Simmons",
    "Black Friday"
  ],
  [
    "Simmons",
    "Black Friday"
  ]
]

I need to get unique arrays only, like:

[
  [
    "Serta",
    "Black Friday"
  ],
  [
    "Simmons",
    "Black Friday"
  ] 
]

I know that for single array element I can use .filter() like:

array.filter((d,i)=>array.indexOf(d)==i)

but I'm not sure for this case, without any library like lodash.

I want to ask for array of arrays that is different @Alexis – Ashutosh Jha Oct 10 '17 at 07:08 — Ashutosh Jha, Oct 10 '17 at 07:08

Nina Scholz · Accepted Answer · 2017-10-10T07:14:08.430

1

You could take a JSON string as key of the array in a hash table and filter with it.

var data = [["Serta", "Black Friday"], ["Serta", "Black Friday"], ["Simmons", "Black Friday"], ["Simmons", "Black Friday"], ["Simmons", "Black Friday"], ["Simmons", "Black Friday"]],
    hash = Object.create(null),
    result = data.filter(a => !hash[JSON.stringify(a)] && (hash[JSON.stringify(a)] = true));

console.log(result);

edited Oct 10 '17 at 07:14

answered Oct 10 '17 at 07:09

Nina Scholz

376,160
25
347
392

1

This may break for entries containing the joining character. – Cerbrus Oct 10 '17 at 07:11
@Cerbrus, not with a json as key. – Nina Scholz Oct 10 '17 at 07:14
Now that the `.join` is edited out, this seems ok. – Cerbrus Oct 10 '17 at 07:15

How to filter out common array in array of arrays

1 Answers1