express

Even making a simple server and adding routes takes a large number of code lines, and code readability decreases. Express, a Node.js framework, solves this problem by providing a much faster way to create the output.

One great thing about Express is that it’s unopinionated, which means it doesn’t hold on to a specific file structure. This feature has its own pros and cons. There are also opinionated options in the market, like NestJS.

github link

Installation

Add a package.json file → → install express

npm init -y

npm i express

if you want you can add nodemon → its a dev dependecy and makes developement easy → we dont have to manually restart server again and again.

npm i nodemon

Some Changes I generally make…

step-1 : create .gitignore file and a src directory.

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.gitignore specifies the files and folders we don't want to push to GitHub. It's a good practice not to push the node_modules folder, as it contains all the installed dependencies, which can be easily recreated using npm install→package.json is an essential file that defines the project's metadata and dependencies. package-lock.json locks the exact versions of the dependencies and their sub-dependencies, ensuring consistency across different environments. It is an autogenerated file and should always be committed along with package.json to maintain dependency integrity.

step-2 : add index.js or index.mjs file → add Scripts in package.json file

I preffer working with ES6 JS so we have to make .js → .mjs OR add “type“:”module” in package.json

made an index.js file and added scripts to run index.js with node and nodemon.

Creating a simple server

Running that server using nodemon via scripts.

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It's a good practice to define the port in a separate PORT variable. Additionally, you should use process.env.PORT to make your application compatible with deployment environments. If process.env.PORT is not included, the code may work on localhost but fail during deployment.

we have not added any routes hence shows this output.

Route Parameters

In request like localhost:3000/api/username → we often require the specific object to be returned back which follows our desired parameters.Here we use request parameters.

this is done by req.params

example →

→ Here, we first have to specify the dynamic segment using : before the parameter.

→ I want to get the user of a specific ID, so I created a route with the dynamic segment :id. To get that key-value pair, we use req.params.id.

→ Then, parse this id into an integer using parseInt.

→ If it’s not an integer, send a status code of 400; else, use .find and a callback function to get the object with the same id.

→ If found, return it, or if not, a status code of 404 is sent.

Query Parameters

Query parameters are often used to send extra data at the endpoints.Typically used to filter,sort or pass additional data.They are part of the URL and come after a ? symbol. Multiple query parameters are separated by &.

this is for the request given as http://localhost:3000/api/users?filter=lastName&value=a

here query parameters are used to filter the objects in api.

Conclusion →

this is a brief intro on express and some basic routing with creating a simple api.

next → different HTTP methods and Middleware.

edit : also planning to add a project using fs module. coming soon

Why Express ?

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