Day 28 – Middlewares - Learning Node JS In 30 Days [Mini series]

Middleware functions are functions that have access to the request object (req), the response object (res), and the next middleware function in the application’s request-response cycle. The next middleware function is commonly denoted by a variable named next. (official document)

Do you understand anything of it ?

In short, normally we use middleware to checking something. Like – if anyone is a authentic user or is the user is admin.

Middleware functions can perform the following tasks:

• Execute any code.
• Make changes to the request and the response objects.
• End the request-response cycle.
• Call the next middleware function in the stack.

An Express application can use the following types of middleware:

• Application-level middleware
• Router-level middleware
• Error-handling middleware
• Built-in middleware
• Third-party middleware

You can check the more details – https://expressjs.com/en/guide/using-middleware.html

Let’s use a middleware

we have 3 elements here – request, response and next cycle here. In the middleware we just console log the time. So when we’ll call the route, this function will be called always.

See the result when we hit the url –

You can see the graphical version here

Originally it published on nerdjfpbblog. You can connect with me in twitter or linkedin !

You can read the old posts from this series (below)

Day 1 — Introduction - Learning Node JS In 30 Days [Mini series]

Muhammad Ali (Nerdjfpb) ・ Dec 4 '19 ・ 1 min read

#node #javascript #codenewbie

Day 2 - Install and Running Node on Window - Learning Node JS In 30 Days [Mini series]

Muhammad Ali (Nerdjfpb) ・ Dec 5 '19 ・ 1 min read

#node #javascript #codenewbie

Day 3 - JavaScript Engine - Learning Node JS In 30 Days [Mini series]

Muhammad Ali (Nerdjfpb) ・ Dec 6 '19 ・ 2 min read

#node #javascript #codenewbie

Day 4 - Window === Global ? - Learning Node JS In 30 Days [Mini series]

Muhammad Ali (Nerdjfpb) ・ Dec 7 '19 ・ 2 min read

#node #javascript #codenewbie

Day 5 - Function Declarations vs. Function Expressions - Learning Node JS In 30 Days [Mini series]

Muhammad Ali (Nerdjfpb) ・ Dec 8 '19 ・ 1 min read

#node #javascript #codenewbie

Day 6 - Require & Module - Learning Node JS In 30 Days [Mini series]

Muhammad Ali (Nerdjfpb) ・ Dec 9 '19 ・ 2 min read

#node #javascript #codenewbie #tutorial

Day 7 - More Modules - Learning Node JS In 30 Days [Mini series]

Muhammad Ali (Nerdjfpb) ・ Dec 10 '19 ・ 2 min read

#node #javascript #codenewbie

Day 8 – Var vs Let vs Const -Learning Node JS In 30 Days [Mini series]

Muhammad Ali (Nerdjfpb) ・ Dec 11 '19 ・ 2 min read

#node #javascript #codenewbie

Day 9 – Mastering EventEmitter - Learning Node JS In 30 Days [Mini series]

Muhammad Ali (Nerdjfpb) ・ Dec 14 '19 ・ 2 min read

#node #javascript #codenewbie

Day 10 – Mastering EventEmitter - Learning Node JS In 30 Days [Mini series]

Muhammad Ali (Nerdjfpb) ・ Dec 14 '19 ・ 2 min read

#node #javascript #codenewbie

Day 11 – Creating and Deleting Folders - Learning Node JS In 30 Days [Mini series]

Muhammad Ali (Nerdjfpb) ・ Dec 15 '19 ・ 2 min read

#node #javascript #codenewbie

Day 12 – Creating own server - Learning Node JS In 30 Days [Mini series]

Muhammad Ali (Nerdjfpb) ・ Dec 15 '19 ・ 2 min read

#node #javascript #codenewbie

Day 13 – Buffer & Stream - Learning Node JS In 30 Days [Mini series]

Muhammad Ali (Nerdjfpb) ・ Dec 16 '19 ・ 2 min read

#node #javascript #codenewbie

Day 14 – Serving HTML Pages - Learning Node JS In 30 Days [Mini series]

Muhammad Ali (Nerdjfpb) ・ Dec 17 '19 ・ 2 min read

#node #javascript #codenewbie

Day 15 – Sending JSON to Client - Learning Node JS In 30 Days [Mini series]

Muhammad Ali (Nerdjfpb) ・ Dec 18 '19 ・ 2 min read

#node #javascript #codenewbie

Day 16 – Routing (Basic) - Learning Node JS In 30 Days [Mini series]

Muhammad Ali (Nerdjfpb) ・ Dec 19 '19 ・ 2 min read

#node #javascript #codenewbie

Day 17 – NPM (Node Package Manager) - Learning Node JS In 30 Days [Mini series]

Muhammad Ali (Nerdjfpb) ・ Dec 20 '19 ・ 3 min read

#node #javascript #codenewbie

Day 18 – Why Express JS ? - Learning Node JS In 30 Days [Mini series]

Muhammad Ali (Nerdjfpb) ・ Dec 21 '19 ・ 2 min read

#node #javascript #codenewbie

Day 19 – Nodemon - Learning Node JS In 30 Days [Mini series]

Muhammad Ali (Nerdjfpb) ・ Dec 22 '19 ・ 3 min read

#node #javascript #codenewbie

Day 20 – Express Js Introduction - Learning Node JS In 30 Days [Mini series]

Muhammad Ali (Nerdjfpb) ・ Dec 23 '19 ・ 2 min read

#node #javascript #codenewbie

Day 21 – HTTP methods - Learning Node JS In 30 Days [Mini series]

Muhammad Ali (Nerdjfpb) ・ Dec 24 '19 ・ 2 min read

#node #javascript #codenewbie

Day 22 – Route Parameters - Learning Node JS In 30 Days [Mini series]

Muhammad Ali (Nerdjfpb) ・ Dec 25 '19 ・ 3 min read

#node #javascript #codenewbie

Day 23 – Template Engines - Learning Node JS In 30 Days [Mini series]

Muhammad Ali (Nerdjfpb) ・ Dec 28 '19 ・ 3 min read

#node #javascript #codenewbie

Day 24 – Working with EJS (Part 1) - Learning Node JS In 30 Days [Mini series]

Muhammad Ali (Nerdjfpb) ・ Dec 29 '19 ・ 3 min read

#node #javascript #codenewbie

Day 25 – Working with EJS (Part 2) - Learning Node JS In 30 Days [Mini series]

Muhammad Ali (Nerdjfpb) ・ Dec 29 '19 ・ 3 min read

#node #javascript #codenewbie

Day 26 – Working with EJS (Part 3) - Learning Node JS In 30 Days [Mini series]

Muhammad Ali (Nerdjfpb) ・ Dec 30 '19 ・ 3 min read

#node #javascript #codenewbie

Day 26 – Working with EJS (Part 3) - Learning Node JS In 30 Days [Mini series]

Muhammad Ali (Nerdjfpb) ・ Dec 30 '19 ・ 3 min read

#node #javascript #codenewbie

Day 27 – Working with Static files - Learning Node JS In 30 Days [Mini series]

Muhammad Ali (Nerdjfpb) ・ Dec 30 '19 ・ 3 min read

#node #javascript #codenewbie