Finding matching values in separate objects

Question

I have two objects:

const have = {
  a: true,
  b: {
    c: true,
    d: true
  }
};

const need = {
  a: false,
  b: {
    c: true,
    d: false
  }
};

I need to find in the "need" obj, if there are at least one positive match (true) with the "have" obj. In this case,they match in b.c, since both are true.

Any ideas how I should face this? maybe first parse to an array? Loop the obj?

Update:

The 'need' obj, does not always contains all the same keys. It might have fewer, but not different.

example:

const need = {
  b: {
    c: true,
  }
};

CertainPerformance · Accepted Answer · 2018-05-09 00:41:49Z

1

If the keys and object structures always match up, you can do a recursive check of the keys/values:

const have = {
  a: true,
  b: {
    c: true,
    d: true
  }
};

const need = {
  a: false,
  b: {
    c: true,
    d: false
  }
};

function objectsHaveMatch(obj1, obj2) {
  return Object.entries(obj1).some(([key, obj1Val]) => {
    if (!obj2[key]) return false;
    if (typeof obj1Val !== 'boolean') return objectsHaveMatch(obj1Val, obj2[key]);
    return obj1Val === true && obj2[key] === true;
	});
}

const atLeastOneMatch = objectsHaveMatch(have, need);
console.log(atLeastOneMatch);

Also works with more complicated structures:

const have = {
  a: true,
  b: {
    c: false,
    d: true,
    foo: {
      q: false,
      w: false,
      e: false,
      r: {
        t: true
      }
    }
  }
};

const need = {
  a: false,
  b: {
    c: true,
    d: false,
    foo: {
      q: true,
      w: true,
      e: true,
      r: {
        t: false
      }
    }
  }
};

function objectsHaveMatch(obj1, obj2) {
  return Object.entries(obj1).some(([key, obj1Val]) => {
    if (!obj2[key]) return false;
    if (typeof obj1Val !== 'boolean') return objectsHaveMatch(obj1Val, obj2[key]);
    return obj1Val === true && obj2[key] === true;
	});
}

const atLeastOneMatch = objectsHaveMatch(have, need);
console.log(atLeastOneMatch);

Snippet example with missing properties:

const have = {
  a: true,
  b: {
    c: true,
    d: true,
    foo: {
      q: false,
      w: false,
      e: false,
      r: {
        t: true
      }
    }
  }
};

const need = {
  b: {
    c: true,
  }
};

function objectsHaveMatch(obj1, obj2) {
  return Object.entries(obj1).some(([key, obj1Val]) => {
    if (!obj2[key]) return false;
    if (typeof obj1Val !== 'boolean') return objectsHaveMatch(obj1Val, obj2[key]);
    return obj1Val === true && obj2[key] === true;
	});
}

const atLeastOneMatch = objectsHaveMatch(have, need);
console.log(atLeastOneMatch);

edited May 9, 2018 at 0:41

answered May 9, 2018 at 0:24

CertainPerformance

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3 Comments

Jonathan Lafleur Over a year ago

I was doing the exact same thing 😂

CertainPerformance Over a year ago

@MarianoZunino Just requires a one-line change: if (!obj2[key]) return false; see edit

Mariano Zunino Over a year ago

@CertainPerformance Amazing! Working like a charm. I will investigate how that magic is works :)

som · Accepted Answer · 2018-05-09 01:33:01Z

0

Similar approach to the accepted answer, except the below is slightly more optimised for the OP's specific use case, assuming the data is 'imitative' and compared values are either an object or 'truthy'.

const have = { a: true, b: { c: true, d: true } };
const need = { b: { c: true } };

const hn = (h, n) => // 'have/need' iterator
  Object.keys(n).some(i => // at least one truthy 'need':
    typeof n[i] === 'object' && hn(h[i], n[i]) // recursive on object
    || n[i] && n[i] === h[i]); // or both h & n are equal and truthy


const has = hn(have, need);
console.log(has);

answered May 9, 2018 at 1:33

som

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