Create a new array with elements that pass a test:
let numbers = [1, 2, 3, 4, 5, 6]
let evens = numbers.filter(n => n % 2 === 0)
console.log(evens) // [2, 4, 6]
let users = [
{ name: "Alice", active: true },
{ name: "Bob", active: false }
]
let activeUsers = users.filter(u => u.active)
console.log(activeUsers) // [{ name: "Alice", active: true }]
The callback returns true to keep an element, false to exclude it.