How to Filter JavaScript Array of Objects by Property Value?

Using Array.prototype.filter()

The Array.prototype.filter() method returns a new array with all elements that satisfy the condition in the provided callback function. Therefore, you can use this method to filter an array of objects by a specific property's value, for example, in the following way:

// ES5+
const employees = [
    { name: 'John', department: 'sales' },
    { name: 'Wayne', department: 'marketing' },
    { name: 'David', department: 'IT' },
    { name: 'Bruce', department: 'marketing' },
];

const filtered = employees.filter(function (emp) {
    return emp.department === 'marketing'
});

console.log(filtered);
/* [
    {name: "Wayne", department: "marketing"},
    {name: "Bruce", department: "marketing"}
] */

If a match is not found then the Array.prototype.filter() method will return an empty array.

With ES6 arrow functions, you can shorten the syntax a bit, for example, like so:

// ES6+
// ...
const filtered = employees.filter((emp) => emp.department === 'marketing');
// ...

In ES6+, you can also directly unpack the object in the callback function's argument, for example, like so:

// ES6+
// ...
const filtered = employees.filter(({ department }) => department === 'marketing');
// ...

Using a Loop

If you're unable to support ES5, then you can simply use a loop (such as a for loop) to iterate over the array of objects and populate a new array with elements you wish to keep. For example:

const employees = [
    { name: 'John', department: 'sales' },
    { name: 'Wayne', department: 'marketing' },
    { name: 'David', department: 'IT' },
    { name: 'Bruce', department: 'marketing' },
];

const match = [];

for (let i = 0; i < employees.length; i++) {
    if (employees[i].department === 'marketing') {
        match.push(employees[i]);
    }
}

console.log(match);
/* [
    {name: "Wayne", department: "marketing"},
    {name: "Bruce", department: "marketing"}
] */

If a match is not found then "match" will be an empty array.