How to create a plugin

Creating a plugin starts by importing the createPlugin function from Fluse.

This function is a generic TypeScript function that requires two generic arguments to be passed:

a type for the plugins context shape, this represents what your plugin will add to the context. In case your plugin doesn't add anything to the context you can use the EmptyContext type which is exported by Fluse.
a type for runtime options that your plugin may use. These runtime options can be used to alter behaviour at runtime. They're mainly used for stateful resources such as database connections.

import { createPlugin } from "fluse";

// Defines what we will put on the context.
// Don't forget to export this type!
export interface MyPluginContext {
  foo: string;
  baz: number;
}

// Defines what we will accept as runtime options.
// Don't forget to export this type!
export interface MyPluginOptions {
  printHello?: boolean;
}

// The plugin
function myPlugin() {
  return createPlugin<MyPluginContext, MyPluginOptions>({
    // Every plugin requires a name.
    // Fluse will use this to report possible issues back to you.
    name: "myplugin",
    // Plugins must specific a semver compatible range.
    version: "0.x",
    // Execute is the method you must implement as a plugin.
    // You'll receieve a next function as well as runtimeOptions (in case you typed them)
    execute(next, runtimeOptions) {
      if (runtimeOptions.printHello) {
        console.log("hello");
      }

      // You must call the next function, and provide your context.
      // Fluse will take care of the rest.
      return next({
        foo: "bar",
        baz: 1,
      });
    },
  });
}

export default myPlugin;

Once we have our plugin, we can use it by setting it up in the initialize:

import { fluse } from "fluse";

export const { fixture, scenario } = fluse({
  plugins: {
    myplugin: myPlugin(),
  },
});

Fixture definitions will now contain a key myplugin which contains the plugins context. Additionally runtime options are now available on the execute method:

const user = await userFixture().execute({
  myplugin: { printHello: true },
});

tip

If your plugin will be published as a separate npm package you should include Fluse as a peerDependency.