Published 2023-03-06
In short, implicit return is returning the value without using the return keyword. With the introduction of arrow functions in ES6, implicit return were made available as well.
Here is the example of function with implicit return:
const getOrderId = () => 'Order-1';
The getOrderId() function above returns a string of Order-1 without using the return keyword.
Now the intention is matter here. Why would I want to use implicit return when I can just do a normal return?
The purpose here is to reduce noise from your code. After reducing noise, the code would be much more concise and readable.
Let's see the example below without implicit return.
// Create proxy middleware for ExpressJS app
function createProxyMiddleware(proxyUrl) {
return function proxy(req, res, next) {
return 'Redirected';
};
}
// Route user path endpoint to user service
app.use('/users', createProxyMiddleware('https://user.service.com'));
Now let's rewrite it with arrow function and implicit return.
// Create proxy middleware for ExpressJS app
const createProxyMiddleware = (proxyUrl) = (req, res, next) => 'Redirected');
// Route user path endpoint to user service
app.use('/users', createProxyMiddleware('https://user.service.com'));
Now, isn't the rewrite look much more concise and cleaner?
You should use it whenever it is possible. But it is ideal for the scenario when you writing a closure and higher-order function like the example above.
By now, you should already know the what, why and when of implicit return in Javascript.
Thanks for reading and see you in the next one.