Find all matching elements with in an array of objects [duplicate]

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.

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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);