JavaScript中两个深层对象的交集

Question

I have two JavaScript objects (of arbitrary depth) that have much of the same information.

I'm looking for help getting the shared data between two objects .

For example:

const a = {
  name: 'Alice',
  features: {
    speed: 3,
    strength: 90,
    mind: {
      power: 42
    }
  }
};

const b = {
  name: 'Bob',
  features: {
    speed: 3,
    stamina: 1,
    mind: {
      power: 42,
      flexibility: 0,
      telekinesis: 42
    }
  }
};

My goal is to come up with a solution to produce the data that they share:

const shared = {
  features: {
    speed: 3,
    mind: {
      power: 42
    }
  }
}

The real data I'm operating on is nested arbitrarily deep (often dozens of objects within objects), but I'm hoping the above examples are helpful.

This is a one-off task so I'm not particularly concerned with performance, and I'm happy to use any library as long as it works. Thanks for the help!

Answer 1

You could use an recursve approach by checking the existence of properties in both objects, truthy properties and same object type or same values.

The use of a variable temp prevents empty nested objects.

 function common(object1, object2) { return Object.assign(...Object.keys(object1).map(k => { var temp; if (!(k in object2)) { return {}; } if (object1[k] && typeof object1[k] === 'object' && object2[k] && typeof object2[k] === 'object') { temp = common(object1[k], object2[k]); return Object.keys(temp).length ? { [k]: temp } : {}; } if (object1[k] === object2[k]) { return { [k]: object1[k] }; } return {}; })); } const a = { name: 'Alice', features: { speed: 3, strength: 90, mind: { power: 42 } } }; b = { name: 'Bob', features: { speed: 3, stamina: 1, mind: { power: 42, flexibility: 0, telekinesis: 42 } } }; console.log(common(a, b)); 

 .as-console-wrapper { max-height: 100% !important; top: 0; } 

Answer 2

You can use the for...in iteration to loop through the object and check it's properties. Please, see in the below code if is that what you want.

 const a = { name: 'Alice', features: { speed: 3, strength: 90, mind: { power: 42 } } }; const b = { name: 'Bob', features: { speed: 3, stamina: 1, mind: { power: 42, flexibility: 0, telekinesis: 42 } } }; function equalProps(a,b){ var newObj = {}; for (var key in a){ if (typeof a[key] === 'object'){ var obj = equalProps(a[key], b[key]); newObj[key] = obj; }else if (a[key] == b[key]){ newObj[key] = a[key]; } } return newObj; } console.log(equalProps(a,b)) 

Answer 3

It looks like the other answers in this thread crashed when an object value was undefined , so I combined the best parts of each answer to come up with a robust solution:

const isObj = x => typeof x === 'object'

const common = (a, b) => {
  let result = {}

  if (([a, b]).every(isObj)) {
    Object.keys(a).forEach((key) => {
      const value = a[key]
      const other = b[key]

      if (isObj(value)) {
        result[key] = common(value, other)
      } else if (value === other) {
        result[key] = value
      }
    })
  }

  return result
}