Getting Started

Mentoss is a utility for mocking JavaScript fetch() requests both in the browser and on server runtimes like Node.js, Deno, and Bun. All of these environments have a global fetch() function capable of making HTTP requests. When testing your JavaScript code, you don’t want to make network requests, so Mentoss is used to simulate those requests and their responses.

Install Mentoss. If you’re using Mentoss in a server-side runtime, you can install it using the package manager of your choice.
- npm
- pnpm
- yarn
- Bun
Install Dependencies
npm install mentoss -D
Install Dependencies
pnpm add mentoss -D
Install Dependencies
yarn add mentoss -D
Install Dependencies
bun install mentoss -D
Create a mock server. Import the MockServer constructor from Mentoss and create a new instance like this:
```
import { MockServer } from "mentoss";

const server = new MockServer("https://api.example.com");
```
The server object is where you can set up the routes that you want to mock. For example:
```
import { MockServer } from "mentoss";

const server = new MockServer("https://api.example.com");

// example route
server.get("/ping", 200);
```
This example creates a route of /ping that returns a 200 status when called.

Mock servers can specify routes in a number of different ways. See XXX for more details.
Create a fetch mocker. A FetchMocker instance is used to create a mocked version of the fetch() function. To create a fetch mocker, import the FetchMocker constructor and specify the server(s) you want to use:
```
import { MockServer, FetchMocker } from "mentoss";

const server = new MockServer("https://api.example.com");

const mocker = new FetchMocker({
  servers: [server],
});
```
Once you have a fetch mocker created, it’s time to use the mocked fetch() function.

Use the mocked fetch() function. Call mockGlobal() and then use fetch() as you normally would:

import { MockServer, FetchMocker } from "mentoss";
import { expect } from "chai";

describe("My API", () => {
    let mocker;

    const server = new MockServer("https://api.example.com");
    mocker = new FetchMocker({
        servers: [server]
    });

    before(() => {
        mocker.mockGlobal();
    });

    // reset the server after each test
    afterEach(() => {
        mocker.clearAll();
    });

    after(() => {
        mocker.unmockGlobal();
    });

    it("should return a 200 status code", async () => {

        // set up the route to test
        server.get("/ping", 200);

        // make the request
        const response = await fetch("https://api.example.com/ping");

        // check the response
        expect(response.status).to.equal(200);
    });
});