Find all matching elements with in an array of objects

Question

I have an array of objects

I am searching within the array like this

let arr = [
    { name:"string 1", arrayWithvalue:"1,2", other: "that" },
    { name:"string 2", arrayWithvalue:"2", other: "that" },
    { name:"string 2", arrayWithvalue:"2,3", other: "that" },
    { name:"string 2", arrayWithvalue:"4,5", other: "that" },
    { name:"string 2", arrayWithvalue:"4", other: "that" },
];
var item  = arr.find(item => item.arrayWithvalue === '4'); 
console.log(item)

This should return an array with this two rows

{ name:"string 2", arrayWithvalue:"4,5", other: "that" },
{ name:"string 2", arrayWithvalue:"4", other: "that" }

It returns only one row which is the first match.

{ name:"string 2", arrayWithvalue:"4", other: "that" }

I do not want to use any external libraries for this. How can I return all the matches that match the criteria?

Answer 1

Two things: first, Array.find() returns the first matching element, undefined if it finds nothing. Array.filter returns a new array containing all matching elements, [] if it matches nothing.

Second thing, if you want to match 4,5, you have to look into the string instead of making a strict comparison. To make that happen we use indexOf which is returning the position of the matching string, or -1 if it matches nothing.

---

Example:

const arr = [
  {
    name: 'string 1',
    arrayWithvalue: '1,2',
    other: 'that',
  },
  {
    name: 'string 2',
    arrayWithvalue: '2',
    other: 'that',
  },
  {
    name: 'string 2',
    arrayWithvalue: '2,3',
    other: 'that',
  },
  {
    name: 'string 2',
    arrayWithvalue: '4,5',
    other: 'that',
  },
  {
    name: 'string 2',
    arrayWithvalue: '4',
    other: 'that',
  },
];

const items = arr.filter(item => item.arrayWithvalue.indexOf('4') !== -1);

console.log(items);