Hi,
Here we are going to learn how to filter the objects in an array with filter() method.
- The filter() method creates an array filled with all array elements that pass a test (provided by a function).
- filter() does not execute the function for empty array elements.
- filter() does not change the original array.
Example 1:
Prepare an array with words which has a length greater than 3 from the following arrray.
let words = ['elephant', 'cat', 'dog', 'tiger', 'lion'];
Without Filter method:
let wordsarray = [];
for (let i = 0; i < words.length; i++) {
if (words[i].length> 3) {
wordsarray.push(words[i]);
}
}
console.log(wordsarray);
Output:
["elephant", "tiger", "lion"]
With filter method:
let wordsarray = [];
wordsarray = words.filter(word => word.length > 3);
console.log(wordsarray );
Output:
["elephant", "tiger", "lion"]
Example 2:
Find the cities whose population is greater than 30000 from the following array.
let cities = [
{name: 'Hyderabad', population: 40000},
{name: 'Karnool', population: 36000},
{name: 'Kadapa', population: 37000},
{name: 'Tirupati', population: 29000}
];
Without Filter method:
let bigCities = [];
for (let i = 0; i < cities.length; i++) {
if (cities[i].population > 30000) {
bigCities.push(cities[i]);
}
}
console.log(bigCities);
Output:
[
{ name: "Hyderabad", population: 40000 },
{ name: "Karnool", population: 36000 },
{ name: "Kadapa", population: 37000 }
]
With filter method:
let bigCities = cities.filter(e => {
return e.population > 30000;
});
console.log(bigCities);
Output:
[
{ name: "Hyderabad", population: 40000 },
{ name: "Karnool", population: 36000 },
{ name: "Kadapa", population: 37000 }
]
Reference:
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/filter
