JavaScript Filter
How to filter arrays in JavaScript using the Array Filter method ?
What does filter function do?
-
The
filter()method creates a new array with array elements that passes a test. -
The
filter()method takes a callback function which has 3 arguments.
Syntax JavaScript Array Filter
array.filter(function(value, index, arr), thisValue)
let numbers = [-11,-22,-33, -1, -5, 0, 2, 42, 32, 19, 85]; let getPostiveNumbers = numbers.filter(number => number >= 0); console.log(getPostiveNumbers); //Output = [0, 2, 42, 32, 19, 85 ]
let users = [ { "name": "Keith", "used": "Samsung Galaxy", "id": "1" }, { "name": "Sum Rae", "used": "OnePlus Nord", "id": "2" }, { "name": "Alan", "used": "OnePlus Nord", "id": "3" }, { "name": "Jonathan", "used": "iPhone 12", "id": "4" }, { "name": "Jarvo", "used": "iPhone 12", "id": "5" } ];
let iPhoneUsers = users.filter(function(user) { return used.used == "iPhone 12"; }); console.log(iPhoneUsers);
[ { name: 'Jonathan', used: 'iPhone 12', id: '4' }, { name: 'Jarvo', used: 'iPhone 12', id: '5' } ]
JavaScript Filter Array
If you more comfortable with arrow functions you can use them to make your code more readable.
let iPhoneUsers = users.filter(user => user.used == "OnePlus Nord"); console.log(iPhoneUsers);
[ { name: 'Sum Rae', used: 'OnePlus Nord', id: '2' }, { name: 'Alan', used: 'OnePlus Nord', id: '3' } ]