filter array based on IDs available in another array

Question

I have two arrays. The first array has only id objects:

arr1 = [
  { id: 1 },
  { id: 2 }
];

and another array has list:

arr2 = [
  { id: 1, name: "kedar" },
  { id: 2, name: "murli" },
  { id: 3, name: "krishnadas" }
];

I need to write arr2 filter function which result as, based on ID available in first array

arr2 = [
  { id: 1, name: "kedar" },
  { id: 2, name: "murli" }
];

Does this answer your question? [How to filter an array from all elements of another array](https://stackoverflow.com/questions/34901593/how-to-filter-an-array-from-all-elements-of-another-array) — chiliNUT, Feb 18 '20 at 14:49

karlmarxlopez · Accepted Answer · 2020-02-18T20:05:36.980

2

const needle = [{
    id: 1
  },
  {
    id: 2
  }
];

const haystack = [{
  id: 1,
  name: 'kedar'
}, {
  id: 2,
  name: 'murli'
}, {
  id: 3,
  name: 'krishnadas'
}];


const filterByIdArray = (ids, arr) =>
  arr.filter(item =>
    ids.find(i =>
      i.id === item.id));

const result = filterByIdArray(needle, haystack);

console.log(result);

edited Feb 18 '20 at 20:05

answered Feb 18 '20 at 09:27

karlmarxlopez

1,019
1
8
16

score 0 · Answer 2 · answered Feb 18 '20 at 09:29

You can create a string using the id value from the first array. So the string will be 1 2, then use filter to create an array of elements from second array and for elements where the id value is included in the string

let arr1 = [{
  id: 1
}, {
  id: 2
}];
let arr2 = [{
  id: 1,
  name: 'kedar'
}, {
  id: 2,
  name: 'murli'
}, {
  id: 3,
  name: 'krishnadas'
}];

let str = arr1.reduce((acc, curr) => {
  acc += ' ' + curr.id

  return acc.trim();
}, '');

let newArr = arr2.filter((item) => {
  // check if id value is included in the string
  return str.indexOf(item.id) != -1;
});

console.log(newArr)

score 0 · Answer 3 · edited Feb 18 '20 at 09:54

0

let a1 = [ {id:1}, {id:2}]
let b1 = [ {id:1, name:'kedar'}, {id:2, name:'murli'}, {id:3, name:'kidu'} ]

let filteredArray = b1.filter(elem => {
      let id_exists = a1.find(id => { return elem.id === id.id });
      return id_exists;
    });
    
console.log(filteredArray);

edited Feb 18 '20 at 09:54

Mohammad Faisal

2,144
15
26

answered Feb 18 '20 at 09:39

diffuse

620
1
7
15

score 0 · Answer 4 · answered Feb 18 '20 at 11:53

0

arr2.filter(el2 => arr1.some(el1 => el1.id === el2.id))

answered Feb 18 '20 at 11:53

chiliNUT

18,989
14
66
106

4

While this code may provide a solution to OP's problem, it is highly recommended that you provide additional context regarding why and/or how this code answers the question. Code only answers typically become useless in the long-run because future viewers experiencing similar problems cannot understand the reasoning behind the solution. – E. Zeytinci Feb 18 '20 at 13:36

filter array based on IDs available in another array

4 Answers4