Generating Errors using HTTP-errors module in Node.js

Last Updated : 06 Apr, 2023

HTTP-errors module is used for generating errors for Node.js applications. It is very easy to use. We can use it with the express, Koa, etc. applications. We will implement this module in an express application.

Installation and Setup: First, initialize the application with the package.json file with the following command:

npm init

Then, install the module by the following command:

npm install http-errors --save

Also, we are using an express application, therefore, install the express module by the following command:

npm install express --save

Now, create a file and name it app.js. You can name your file whatever you want.

For importing the modules in your application, write the following code in your app.js file:

javascript

   const createError = require('http-errors');
const express = require('express');
const app = express();
 
  

Implementation: Here, comes the main part of our application. For using this module, write the following code in your app.js file:

javascript

   // Node program to demonstrate the
const createError = require('http-errors');
const express = require('express');
const app = express();
 
app.use((req, res, next) => {
    if (!req.user) return next(
        createError(401, 'Login Required!!'));
    next();
});
 
app.listen(8080, (err) => {
    if (err) console.log(err);
    console.log(
        `Server Running at http://localhost:8080`);
});
 
  

Here, we are importing the http-errors module and storing it in a variable named as createError. Next, in app.use(), if the user is not authenticated, then our application will create a 401 error saying Login Required!!. The createError is used for generating errors in an application.

To run the code, run the following command in the terminal:

node app.js

and navigate to http://localhost:8080. The output for the above code will be:

List of all Status Codes with their Error Message:

Status Code    Error Message  400    BadRequest 401    Unauthorized 402    PaymentRequired 403    Forbidden 404    NotFound 405    MethodNotAllowed 406    NotAcceptable 407    ProxyAuthenticationRequired 408    RequestTimeout 409    Conflict 410    Gone 411    LengthRequired 412    PreconditionFailed 413    PayloadTooLarge 414    URITooLong 415    UnsupportedMediaType 416    RangeNotSatisfiable 417    ExpectationFailed 418    ImATeapot 421    MisdirectedRequest 422    UnprocessableEntity 423    Locked 424    FailedDependency 425    UnorderedCollection 426    UpgradeRequired 428    PreconditionRequired 429    TooManyRequests 431    RequestHeaderFieldsTooLarge 451    UnavailableForLegalReasons 500    InternalServerError 501    NotImplemented 502    BadGateway 503    ServiceUnavailable 504    GatewayTimeout 505    HTTPVersionNotSupported 506    VariantAlsoNegotiates 507    InsufficientStorage 508    LoopDetected 509    BandwidthLimitExceeded 510    NotExtended 511    NetworkAuthenticationRequired

Conclusion: The HTTP-errors module is very useful for developers for the quick generation of errors in their messages. In this article, we learned about the HTTP-errors module for Node.js. We have also seen its installation and Implementation.