The filter() method accepts a test function, and returns a new array containing only the elements of the original array that pass the test provided.
// Suppose we want to get all odd number in an array:
var numbers = [5, 32, 43, 4];var odd = numbers.filter(function(n) {
return n % 2 !== 0;
});let odd = numbers.filter(n => n % 2 !== 0); // can be shortened to (n => n % 2)
odd would contain the following array: [5, 43].
It also works on an array of objects:
var people = [{
id: 1,
name: "John",
age: 28
}, {
id: 2,
name: "Jane",
age: 31
}, {
id: 3,
name: "Peter",
age: 55
}];var young = people.filter(function(person) {
return person.age < 35;
});let young = people.filter(person => person.age < 35);young would contain the following array:
[{
id: 1,
name: "John",
age: 28
}, {
id: 2,
name: "Jane",
age: 31
}]You can search in the whole array for a value like this:
var young = people.filter((obj) => {
var flag = false;
Object.values(obj).forEach((val) => {
if(String(val).indexOf("J") > -1) {
flag = true;
return;
}
});
if(flag) return obj;
});This returns:
[{
id: 1,
name: "John",
age: 28
},{
id: 2,
name: "Jane",
age: 31
}]