Array.filter() is one of the built-in methods available for arrays that takes in an array and creates a new array containing data based on a criteria.

Structure

const newArray = originalArray.filter((nameOfParam) => {
    return nameOfCondition;
});

Using ES5 syntax:

var newArray = originalArray.filter(function(nameOfParam){
    return nameOfCondition;
});

Examples

Return the name of a fruit that has greater than 6 characters

const fruits = ['apple', 'orange', 'bananas', 'grapes'];

const filteredFruit = fruits.filter((fruit) => {
  return fruit.length > 6;
});

console.log(filteredFruit); // ['bananas']

Return the names and positions of users in a certain department

const users = [
    {name: 'Tom Smith', position: 'Senior Engineer', department: 'IT'},
    {name: 'Danielle Layton', position: 'Head of Marketing', department: 'Marketing'},
    {name: 'Peter Jacobsen', position: 'IT Manager', department: 'IT'},
    {name: 'Laura Johnson', position: 'Senior Sales Representative', department: 'Sales'},
    {name: 'Jessica Jones', position: 'Intermediate Software Engineer', department: 'IT'}
];

const listUsersFromDepartment = users.filter((usersInDept) => {
  return usersInDept.department === 'IT';
});

console.log(listUsersFromDepartment); //[
  { name: 'Tom Smith', position: 'Senior Engineer', department: 'IT' },
  { name: 'Peter Jacobsen', position: 'IT Manager', department: 'IT' },
  { name: 'Jessica Jones',  position: 'Intermediate Software Engineer', department: 'IT'}
]