Returning Multiple Values from a Function
JavaScript functions can return a single value. To return multiple values from a function, you can pack the return values as elements of an array or as properties of an object.
Returning multiple values from a function using an array
Suppose the following getNames() function retrieves the first name and last name from a database in the backend or from the result of a third-party API call and returns them as elements of an array:
function getNames() {
// get names from the database or API
let firstName = 'John',
lastName = 'Doe'; // return as an array
return [firstName, lastName];
}
Code language: JavaScript (javascript)
The following shows how to get the return value from the getNames() function:
let names = getNames();Code language: JavaScript (javascript)
Because the names variable is an array, you can reference its elements using the square brackets, like this:
const firstName = names[0],
lastName = names[1];Code language: JavaScript (javascript)
In ES6, you can use the destructuring assignment syntax to unpack values from an array more intuitively, like this:
const [firstName, lastName] = getNames();Code language: JavaScript (javascript)
In this code, the firstName and lastName variables will take the first and second elements of the return array.
Returning multiple values from a function using an object
If you want to assign a name to each returned value to make it more readable and easier to maintain, you can use an object:
function getNames() {
// get names from the database or API
let firstName = 'John',
lastName = 'Doe'; // return values
return {
'firstName': firstName,
'lastName': lastName
};
}
Code language: JavaScript (javascript)
Since the names of the properties are the same as the variables, you can shorten it using the object literal syntax extensions in ES6 as follows:
function getNames() {
// get names from the database or API
let firstName = 'John',
lastName = 'Doe'; return { firstName, lastName };
}
Code language: JavaScript (javascript)
And you can get the return value as an object like this:
let names = getNames();let firstName = names.firstName,
lastName = names.lastName;
Code language: JavaScript (javascript)
If you want to unpack properties from an object, you can use the object destructuring syntax as follows:
let { firstName, lastName } = getNames();Code language: JavaScript (javascript)
Summary
- JavaScript doesn’t support functions that return multiple values. However, you can wrap multiple values into an array or an object and return the array or the object.
- Use destructuring assignment syntax to unpack values from the array, or properties from objects.