Filter array of objects based on another array of objects in javascript

Question

I have an array like this

arr1 =
[
   {A: 'red', B: 'blue'},
   {Q: 'green', R: 'blue'},
   {B: 'green', M: 'red'},
   {Q: 'white', R: 'blue'},
   ...
]

Each object has two key/value pairs, a letter and color. I have another array like this

filter=
[
   {A: 'val', B: 'someval'},
   {B: 'anothervalue', M: 'value'}
]

Is it possible to filter the first array such that the final result is an array that only has the objects that have the same keys as the second array. (without a for or while loop)

In this scenario it would be:

[
   {A: 'red', B: 'blue'},
   {B: 'green', M: 'red'}
]

So I want something like:

let filteredArr = arr1.filter(obj => 
    Object.keys(obj) == Object.keys(filter[someKey]));

But I'm not sure how to do this without looping over all the keys of filter .

Answer 1

You could use a Set for the property names and filter the array.

 var array = [{ A: 'red', B: 'blue' }, { Q: 'green', R: 'blue' }, { B: 'green', M: 'red' }, { Q: 'white', R: 'blue' }], filter = [{ A: 'val', B: 'someval' }, { B: 'anothervalue', M: 'value' }], getKey = o => Object.keys(o).sort().join('|'), result = array.filter((s => o => s.has(getKey(o)))(new Set(filter.map(getKey)))); console.log(result); 

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Answer 2

You can do this with fiter() , some() and every()

 var arr1 = [{"A":"red","B":"blue"},{"Q":"green","R":"blue"},{"B":"green","M":"red"},{"Q":"white","R":"blue"}] var filter = [{"A":"val","B":"someval"},{"B":"anothervalue","M":"value"}] var result = arr1.filter(function(e) { return filter.some(function(a) { var keyE = Object.keys(e); var keyA = Object.keys(a); return keyE.length == keyA.length && keyE.every(function(k) { return keyA.includes(k) }) }) }) console.log(result)