Mock Express Request

0.2.2 · abandoned · verified Wed Apr 22

Mock Express Request is a Node.js library designed to create mock HTTP request objects for unit testing Express.js applications. It is based on the `mock-req` package and aims to provide an instance with properties and methods similar to a real Express HTTP request. The package is currently at version 0.2.2 and appears to be abandoned, with no significant updates or maintenance activity in approximately nine years. Due to its age, it lacks modern features such as native ES Module support and deep integration with contemporary testing frameworks like Jest, making it less suitable for current Node.js and Express.js projects. Developers are generally advised to consider more actively maintained alternatives like `node-mocks-http` or `@jest-mock/express` for robust testing in modern environments.

Common errors

```
TypeError: MockExpressRequest is not a constructor
```
cause Attempting to import the CommonJS module using ES Module `import` syntax (e.g., `import MockExpressRequest from 'mock-express-request';`).

fix Change the import statement to CommonJS `const MockExpressRequest = require('mock-express-request');`.
```
TypeError: request.body is undefined
```
cause While `body` can be passed to the constructor, Express typically populates `req.body` via body-parser middleware. This mock might not automatically process raw request data into `req.body` in the same way, leading to `undefined` if not explicitly set in the mock constructor options.

fix Ensure `req.body` is explicitly defined in the `MockExpressRequest` constructor options, for example: `new MockExpressRequest({ body: { key: 'value' } })`.

Warnings

breaking This package is effectively unmaintained since 2017. It may not be compatible with newer versions of Node.js or Express.js, potentially leading to unexpected behavior or missing features found in modern Express request objects.
Fix: Consider migrating to actively maintained alternatives like `node-mocks-http` or `@jest-mock/express` for modern Express environments.
gotcha The package exclusively uses CommonJS `require()`. It does not provide ES Module exports, and attempting to use `import` syntax will result in a runtime error.
Fix: Always use `const MockExpressRequest = require('mock-express-request');` for importing the library.
gotcha The mock objects created by this library are simple POJOs extended with Express-like methods. They might not fully replicate the complex behavior, event emitters, or stream aspects of a real Express request, which can be crucial for testing advanced middleware.
Fix: For comprehensive testing of complex Express features, consider using integration tests with tools like Supertest, or more robust mocking libraries that offer deeper Express API simulation and Jest/Sinon integration.

Install

npm install mock-express-request npm
yarn add mock-express-request yarn
pnpm add mock-express-request pnpm

Imports

MockExpressRequest
wrong:
```
import MockExpressRequest from 'mock-express-request';
```
correct:
```
const MockExpressRequest = require('mock-express-request');
```
This package is CommonJS-only. Attempting to use ES module import syntax will result in a TypeError.
MockExpressRequest (instance)
```
const request = new MockExpressRequest({ method: 'GET', url: '/test' });
```
The primary use case is to instantiate the class with an options object to configure the mock request properties.

Quickstart

Demonstrates how to create basic and advanced mock Express HTTP request objects, configuring method, URL, headers, cookies, and body, then accessing these properties.

const MockExpressRequest = require('mock-express-request');

// Basic usage: Create a mock GET request to a specific URL
const basicRequest = new MockExpressRequest({
    method: 'GET',
    url: '/api/users/123?profile=full'
});

console.log(`Method: ${basicRequest.method}`); // Expected: GET
console.log(`URL: ${basicRequest.url}`);       // Expected: /api/users/123?profile=full
console.log(`Path: ${basicRequest.path}`);     // Expected: /api/users/123
console.log(`Query 'profile': ${basicRequest.param('profile')}`); // Expected: full

// More advanced usage: Mock a PUT request with headers and cookies
const advancedRequest = new MockExpressRequest({
    method: 'PUT',
    url: '/data/item/abc',
    cookies: { session_id: 'MY_SESSION_TOKEN', remember_me: 'true' },
    headers: {
        'Accept': 'application/json',
        'Content-Type': 'application/json',
        'Authorization': 'Bearer ABCDEFG'
    },
    body: { name: 'New Item', value: 42 }
});

console.log(`Host: ${advancedRequest.hostname}`); // Access Express-like properties (often defaults to 'localhost')
console.log(`Request body: ${JSON.stringify(advancedRequest.body)}`);
console.log(`Cookie 'session_id': ${advancedRequest.cookies.session_id}`);
console.log(`Header 'Content-Type': ${advancedRequest.get('Content-Type')}`); // Using .get() for headers

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