javascript object filter

1// use filter() function. Let say we have array of object.
2let arr = [
3  {name: "John", age: 30},
4  {name: "Grin", age: 10},
5  {name: "Marie", age: 50},
6];
7//Now I want an array in which person having age more than 40 is not
8//there, i.e, I want to filter it out using age property. So
9let newArr = arr.filter((person)=>(return person.age <= 40));
10//filter function expects a function if it return true then it added 
11//into new array, otherwise it is ignored. So new Array would be
12/* [
13	{name: "John", age: 30},
14  	{name: "Grin", age: 10},
15   ]
16*/

1var heroes = [
2	{name: “Batman”, franchise: “DC”},
3	{name: “Ironman”, franchise: “Marvel”},
4	{name: “Thor”, franchise: “Marvel”},
5	{name: “Superman”, franchise: “DC”}
6];
7
8var marvelHeroes =  heroes.filter(function(hero) {
9	return hero.franchise == “Marvel”;
10});
11
12// [ {name: “Ironman”, franchise: “Marvel”}, {name: “Thor”, franchise: “Marvel”} ]

1function objectFilter = (obj, predicate) => 
2    Object.keys(obj)
3          .filter( key => predicate(obj[key]) )
4          .reduce( (res, key) => (res[key] = obj[key], res), {} );
5
6// Example use:
7var scores = {
8    John: 2, Sarah: 3, Janet: 1
9};
10
11var filtered = objectFilter(scores, num => num > 1); 
12console.log(filtered);

1/** filter object by key or value */
2
3/** filter object function */
4function filterObj( obj, predicate ) {
5	var result = {}, key;
6
7	for ( key in obj ) {
8		if ( obj.hasOwnProperty( key ) && predicate( key, obj[ key ] ) ) {
9			result[ key ] = obj[ key ];
10		}
11	}
12
13	return result;
14};
15
16// example
17
18// set object
19var obj = {
20	name : 'john',
21	lastName : 'smith',
22	age : 32
23}
24
25// filter out parameters using key and value
26var filteredObj = filterObj( obj, function( key, value ) {
27	return key !== 'age' && value !== 'smith'
28});
29
30// show result
31console.log( filteredObj ); // { name: "john" }

1const filterThisArray = ["a","b","c","d","e"] 
2console.log(filterThisArray) // Array(5) [ "a","b","c","d","e" ]
3
4const filteredThatArray = filterThisArray.filter((item) => item!=="e")
5console.log(filteredThatArray) // Array(4) [ "a","b","c","d" ]
6

1let newArray = array.filter(function(item) {
2  return condition;
3});