What is express.json() — A Quick Overview

When someone sends data to the server, they often send it in a certain format. One common format is JSON (which stands for JavaScript Object Notation). This is a way to represent data like:

{
  "name": "John",
  "age": 30
}

Now, when server receives this data, it needs to understand it. Without the right tool, it would just look like a bunch of text.

What does express.json() do?

express.json() is like a helper for the server that converts this text (JSON data) into something the server can understand and work with easily (a JavaScript object).

When a client sends a request with JSON data, like:

{
  "name": "John",
  "age": 30
}

Without express.json(), the server wouldn't know how to handle that data. But when we use app.use(express.json()), it automatically converts the JSON data into a JavaScript object so we can access it easily, like this:

app.post('/user', (req, res) => {
  console.log(req.body); // { name: 'John', age: 30 }
});

So in short, express.json() is used to automatically convert JSON data from the request into a JavaScript object, making it easy to work with.