Check if array exists in another array with lodash

Question

Is it possible to check if an array

A=[
  "EMPRESA",
  "CD_MAQ",
  "DT_INI_MAQ"
]

Exists in another array

B=[
  "EMPRESA",
  "CD_MAQ",
  "DT_INI_MAQ",
  "CD_WKC",
  "DT_INI_WKC"
]

I want to check if all entries in array A exists in B

You could just check if the [**intersection**](https://lodash.com/docs/4.16.2#intersection) of the two arrays are of equal length to array A: `var completeIntersect = _.intersection(A, B).length === A.length;` — Tholle, Oct 03 '16 at 13:44

score 37 · Accepted Answer · answered Oct 03 '16 at 13:47

var A=[
  "EMPRESA",
  "CD_MAQ",
  "DT_INI_MAQ"
];

var B=[
  "EMPRESA",
  "CD_MAQ",
  "DT_INI_MAQ",
  "CD_WKC",
  "DT_INI_WKC"
];

if ( _.difference(A,B).length === 0){
  // all A entries are into B
}

<script src="https://cdn.jsdelivr.net/lodash/4.16.2/lodash.min.js"></script>

Just use _.difference

score 9 · Answer 2 · answered Oct 03 '16 at 13:49

You can use the intersection of the 2 arrays, and then compare to the original.

var A=[
  "EMPRESA",
  "CD_MAQ",
  "DT_INI_MAQ"
];

var B=[
  "EMPRESA",
  "CD_MAQ",
  "DT_INI_MAQ",
  "CD_WKC",
  "DT_INI_WKC"
];

console.log(_.isEqual(_.intersection(B,A), A));

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Check if array exists in another array with lodash

2 Answers2