javascript filter on object properties 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: Object properties filter from properties js

const raw = {
  item1: { key: 'sdfd', value:'sdfd' },
  item2: { key: 'sdfd', value:'sdfd' },
  item3: { key: 'sdfd', value:'sdfd' }
};

const allowed = ['item1', 'item3'];

const filtered = Object.keys(raw)
  .filter(key => allowed.includes(key))
  .reduce((obj, key) => {
    obj[key] = raw[key];
    return obj;
  }, {});

console.log(filtered);