How to check if an object contains another object like

Question

const LHS = {
a : "Something a",
b : "Something b",
c : { a : "Something a"}
}

let RHS = {
a : "Something a",
c : { a : "Something a"}
}

// How to write a function contains which replicates this behaviour

contains(LHS, RHS) // should return true

 RHS = {
a : "Something a",
c : { a : "Something a"},
d : "Something d"
}

contians(LHS, RHS) // Should return false

I have abosulety no Idea how to do that. If you know some external libaries that does this please share it.

Thanks

score 1 · Accepted Answer · answered Feb 06 '21 at 06:36

So you want to check if all the key/value pairs within one object are also contained within another object? That's very similar to this thread, from which I found the easiest method to check is to use this answer combined with isEqual. Yes, bringing in libraries/modules is a hassle, but regardless, it's about as optimized as this operation could be.

const LHS = {
  a: "Something a",
  b: "Something b",
  c: {
    a: "Something a"
  }
}

let RHS = {
  a: "Something a",
  c: {
    a: "Something a"
  }
}

both = _.merge(_.cloneDeep(LHS), RHS);

console.log(_.isEqual(both, LHS));

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.20/lodash.min.js"></script>

This code will duplicate the first object (LHS) and merge that with the second (RHS) - those should be identical if all key/value pairs in RHS are also in LHS.

JSFiddle

How to check if an object contains another object like

1 Answers1