Check if array exists in array using lodash

Question

How do I verify if a child array exists in its parent? I have tried _.includes, _.find and _.findIndex without any luck.

let arr = [[1],[2],[3]];
let el = [1];

_.includes(arr, el)   // false
_.find(arr, el)       // undefined
_.findIndex(arr, el)  // -1

To clarify, the el is an array that contains n amount of integers, whilst arr is an array that contains n amount of arrays.

[1] is not equal to another [1] because they're really different objects with the same content — apokryfos
– apokryfos, Commented Apr 30, 2018 at 22:52

Dekel · Accepted Answer · 2018-04-30 22:51:47Z

3

You will have to walk over the array and compare it's elements.

You can use the _.isEqual function to do so:

let arr = [[1],[2],[3]];
let el = [1];

console.log(arr.filter((e) => _.isEqual(e, el)))

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.10/lodash.min.js"></script>

answered Apr 30, 2018 at 22:51

Dekel

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Comments

apokryfos · Accepted Answer · 2018-04-30 22:55:15Z

3

Since Lodash is your weapon of choice here you can do:

_.findIndex(arr, function (v) { return _.isEqual(v, el); }); // 0

answered Apr 30, 2018 at 22:55

apokryfos

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Rob M. · Accepted Answer · 2018-04-30 23:18:36Z

2

If your arrays are ordered you don't have to walk each of them:

let arr = [[1],[2],[3]];
let el = [1];

console.log(
  arr.some(arr => arr.toString() === el.toString())
)

answered Apr 30, 2018 at 23:18

Rob M.

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