const clothing = ['shoes', 'shirts', 'socks', 'sweaters']; console.log(clothing.length); // expected output: 4
let data = [ { "id": 1, "is_read": true, }, { "id": 2, "is_read": true, }, { "id": 3, "is_read": false, }, { "id": 4, "is_read": true, }, ], length = data.filter(function(item){ return item.is_read; }).length; console.log(length)