NodeJS ToDo App

This is a very basic app created with nodejs.

To make things simple I used this great framework called Express.

Express is a framework that sits on top on Node.js to simplify its API and remove some of its complexity and add some nice features like routing and middleware.

Routing is a very important feature offered by express. According to its documentation:

Routing refers to determining how an application responds to a client request to a particular endpoint, which is a URI (or path) and a specific HTTP request method (GET, POST, and so on).

Each route can have one or more handler functions, which are executed when the route is matched.

Route definition takes the following structure:

app.METHOD(PATH, HANDLER)

Where:

• app is an instance of express.
• METHOD is an HTTP request method, in lowercase.
• PATH is a path on the server.
• HANDLER is the function executed when the route is matched.

Methods

Here are some of the main methods available:

• GET: Fetch data information from the server.

• POST: Send information to the server.

• PUT: Change information.

• PATCH: Change specific information.

• DELETE: Delete information.

Params

The routes accept some params. Some of them are:

• Route Params: edit, delete and search a resource.

In the example below the :id is the param we need to know what todo we are talking about. To get the id we use the request params property, like this: req.params.id.

app.put("/todo/:id", (req, res) => {
  const id = req.params.id;
});

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NOTE

Once we define a param if we don't pass it to the url param we get a error. So if we call just example.com/todo and we didn't define a basic url we get an error. We need to specify the param, like this: example.com/todo/1.

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• Query Params: used to dynamically pass information in URL.

It is commonly used to create pagination. For example:

example.com/pagination?page=1&total=20

Everything after ? is a query string.

We can access query strings with request query property. Check it out!

app.put("/pagination", (req, res) => {
  const page = req.query.page;
});

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NOTE

Different from the Route Params, the Query Params are optional, so something like: examle.com/pagination will work just fine. Then ?page=1&total=20 is not required.

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• Body Params: used to insert and alter information, usually in a json format.

We can access body params with request body property.

app.put("/todo", (req, res) => {
  const title = req.body.title;
});

Or using destructuring:

app.put("/todo", (req, res) => {
  const { id, title } = req.body;
});

Assuming we have something like this:

{
  "id": 1,
  "title": "New Title"
}

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NOTE

Express accept several format files, so in order to it understand we are using a json file we need to use a middleware:

app.use(express.json());

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