filter value in array of object and array javascript code example

Example 1: how to filter object in javascript

// use filter() function. Let say we have array of object.
let arr = [
  {name: "John", age: 30},
  {name: "Grin", age: 10},
  {name: "Marie", age: 50},
];
//Now I want an array in which person having age more than 40 is not
//there, i.e, I want to filter it out using age property. So
let newArr = arr.filter((person)=>(return person.age <= 40));
//filter function expects a function if it return true then it added 
//into new array, otherwise it is ignored. So new Array would be
/* [
	{name: "John", age: 30},
  	{name: "Grin", age: 10},
   ]
*/

Example 2: can filter be used on objects in javascript

var heroes = [
	{name: “Batman”, franchise: “DC”},
	{name: “Ironman”, franchise: “Marvel”},
	{name: “Thor”, franchise: “Marvel”},
	{name: “Superman”, franchise: “DC”}
];

var marvelHeroes =  heroes.filter(function(hero) {
	return hero.franchise == “Marvel”;
});

// [ {name: “Ironman”, franchise: “Marvel”}, {name: “Thor”, franchise: “Marvel”} ]

Example 3: array.filter in javascript

//Eg 1 - If item is unchecked, remove it from array

const array = [2, 3, 4]

if (event.target.checked) {
      newValue.push(option);
    } else {
      newValue = newValue.filter(item => item.id != option.id);
    }

//If false, it will remove the element. 2 is not equal to 2.

//Eg 2 - To return an array with length > 6

const words = ['spray', 'limit', 'elite', 'exuberant', 'destruction', 'present'];
const result = words.filter(word => word.length > 6);