how filter works in javascript code example

Example 1: filter javascript array

var words = ['spray', 'limit', 'elite', 'exuberant', 'destruction', 'present'];

const result = words.filter(word => word.length > 6);

console.log(result);

Example 2: how the filter() function works javascript

const arr = [1, 2, 3, 4, 5, 6, 7, 8, 9];

const filter = arr.filter((number) => number > 5);
console.log(filter); // [6, 7, 8, 9]

Example 3: js filter object

/** filter object by key or value */

/** filter object function */
function filterObj( obj, predicate ) {
	var result = {}, key;

	for ( key in obj ) {
		if ( obj.hasOwnProperty( key ) && predicate( key, obj[ key ] ) ) {
			result[ key ] = obj[ key ];
		}
	}

	return result;
};

// example

// set object
var obj = {
	name : 'john',
	lastName : 'smith',
	age : 32
}

// filter out parameters using key and value
var filteredObj = filterObj( obj, function( key, value ) {
	return key !== 'age' && value !== 'smith'
});

// show result
console.log( filteredObj ); // { name: "john" }

Example 4: filter javascript

const arr = [1, 2, 3, 4, 5, 6, 7, 8, 9];

const filter = arr.filter((number) => number > 5);
console.log(filter); // [6, 7, 8, 9]

or 

const words = ['spray', 'limit', 'elite', 'exuberant', 'destruction', 'present'];

const result = words.filter(word => word.length > 6);

console.log(result);
// expected output: Array ["exuberant", "destruction", "present"]

Example 5: 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);

Example 6: javascript array filter

run.addEventListener("click", function () {
    let array = [];
    people.forEach((elem) => {
      // elem before age to target
      if (elem.age > 18) {
        array.push(elem); // each array elem > 18 is "pushed" inside the new array
        // console.log(array); nope : messes things up
      } else {
        (""); // no need to declare this through console.log
      }
    });
    console.log(array); //and there you have it : filtered array
  });