Find if an object is subset of another object in javascript

Using Lodash isMatch

_.isMatch({prop: 'object', id: 3}, {prop: 'object'})

Performs a partial deep comparison between object and source to determine if object contains equivalent property values.

It's a bit late, but it might help someone looking for answer without using any external library.

isSubset = (superObj, subObj) => {
    return Object.keys(subObj).every(ele => {
        if (typeof subObj[ele] == 'object') {
            return isSubset(superObj[ele], subObj[ele]);
        }
        return subObj[ele] === superObj[ele]
    });
};

let object1 = { pickUpLocation : {city : 'Hyderabad', state: 'Telangana' }};
let object2 = { dist : 322, pickUpLocation:  {city : 'Hyderabad', state: 'Telangana' }};
console.log(isSubset(object2, object1));

let object3 = { pickUpLocation : {city : 'Chennai', state: 'Telangana' }}
let object4 = { dist : 322, pickUpLocation: {city : 'Hyderabad', state: 'Telangana' }}
console.log(isSubset(object4, object3));

It can be done pretty easily with lodash.

import _ from 'lodash'

const isSubset = (aSubset, aSuperset) => (
    _.every(aSubset, (val, key) => _.isEqual(val, aSuperset[key]))
)

Usage:

const object1 = { pickUpLocation: { city: 'Hyderabad', state: 'Telangana' }}
const object2 = { dist: 322, pickUpLocation:  { city: 'Hyderabad', state: 'Telangana' }}

isSubset(object1, object2)

You can try to use isSubset package.

This is true

isSubset(
  { dist : 322, pickUpLocation:  {city : 'Hyderabad', state: 'Telangana' }},
  { pickUpLocation : {city : 'Hyderabad', state: 'Telangana' }}
);

This is false

isSubset(
  { dist : 322, pickUpLocation:  {city : 'Hyderabad', state: 'Telangana' }},
  { pickUpLocation : {city : 'Chennai', state: 'Telangana' }}
);

The above answer using lodash has limitation and doesn't cover all edge case scenarios. I just came up with this solution that matches all scenarios

import _ from 'lodash';

isSubset(obj1, obj2) {
  let matched = true;
  _.forEach(obj1, (value, key) => {
    if(!requirements || !_.isEqual(value, obj2[key])) {
      matched = false;
      return;
    }
  });
  return matched;
}

Case 1:

const obj1 = { foo: 'bar' };
const obj2 = { foo: 'bar', baz: 'qux' };
console.log(isSubset(obj1, obj2)); // true

Case 2:

const obj1 = { foo: 'bar' };
const obj2 = { foo: 'bar' };
console.log(isSubset(obj1, obj2)); // true

Case 3:

const obj1 = { foo: 'bar', baz: 'qux' };
const obj2 = { foo: 'bar'};
console.log(isSubset(obj1, obj2)); // false

Case 4:

const obj1 = undefined;
const obj2 = undefined;
console.log(isSubset(obj1, obj2)); // true

Case 5:

const obj1 = undefined;
const obj2 = { foo: 'bar'};
console.log(isSubset(obj1, obj2)); // true

Case 6:

const obj1 = { foo: 'bar'};
const obj2 = undefiend;
console.log(isSubset(obj1, obj2)); // false

Nima's first answer cannot be right since for a subset condition to be true, all (not just some) elements in the "smaller" set need to be contained in the "bigger" set. The rest is basically correct though, just replace some with every, and swap the two objects (big and small):

/**
 * Determine whether "small" is a subset of "big"
 * @see https://stackoverflow.com/questions/35737312/find-if-an-object-is-subset-of-another-object-in-javascript/48971177#48971177
 */
function isSubset(big, small) {
  const { every, isEqual } = _;
  return every(small, 
    (v, k) => isEqual(v, big[k])
  );
}

// test it!
var object1 = { pickUpLocation : {city : 'Hyderabad', state: 'Telangana' }};
var object2 = { dist : 322, pickUpLocation:  {city : 'Hyderabad', state: 'Telangana' }};
var a = {i:1, j:2, k:3}; var b = {i:1, j:2}; var c = {i:2, j:2};

console.log([
  isSubset(a, b),
  isSubset(a, c),
  isSubset(b, a),
  isSubset(object1, object2),
  isSubset(object2, object1)
]);

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.js"></script>

PS: Here is another way of doing it, but it's probably slower since it copies stuff and does not stop early:

function isSubset(big, small) { 
  const { pick, isEqual } = _;
  return isEqual(pick(big, Object.keys(small)), small);
}

Here is a simple solution:

  import _ from "lodash"
  // is a subset of b?
  function isSubset(a, b, merge = false) {
    const assign = merge ? _.merge : _.assign;
    var c = assign(_.cloneDeep(b), a);
    return _.isEqual(b, c);
  }

A bit late too, but here's another solution that doesn't require any external libraries. I based this off @Akshay Kapoor's answer, but this one handles equality for Dates and other objects that define valueOf():

const isSubset = (superObj, subObj) =>
    superObj === subObj ||
    typeof superObj === "object" &&
    typeof subObj === "object" && (
        subObj.valueOf() === superObj.valueOf() /* dates & ? */ ||
        Object.keys(subObj).every(k => isSubset(superObj[k], subObj[k]))
    );

function isSubset(obj1, obj2) {
  const matches = [];
  for(const n1 in obj1) {
    let match = false;
    for(const n2 in obj2) {
      if(n1 == n2 && obj1[n1] == obj2[n2]) {
        match = true;
        break;
      }
    }
    matches.push(match);
  }
  return matches.every(Boolean);
}

function isSubset(obj1, obj2) {
  for (var key in obj2){
     if (JSON.stringify(obj2[key]) === JSON.stringify(obj1[key]))
        return true;
  }
  return false;
}

Edit: Now is generic, but if want it more generic you should see the follow link for the comparison https://stackoverflow.com/a/1144249/5965782

In English:

Is there some key in object2 which satisifies the condition that there is deep equality between its value and object1?

Write that out:

_.some(                       // Is there some key
  object2,                    // in object2
  function(val, key) {             // which satisfies the condition that
    return _.isEqual(         // there is deep equality between
      val,                    // its value and
      object1[key]                 // object1?
    );
  }
);

In shorter form:

_.some(object2, function(val, key) { return _.isEqual(val, object1[key]); })

In ES6:

_.some(object2, (val, key) => _.isEqual(val, object1[key]))

My suggestion is to read through the lodash docs and learn all the APIs, or at least the main ones. For example, this problem will be very difficult to solve on your own if you are not aware of important routines such as _.some and _.isEqual. On the other hand, if you do know them, then it is quite trivial.