plugin-hooks

plugin-hooks is a Typescript npm package that provides the ability to compose and execute functions as a chain of plugins. It supports both synchronous and asynchronous plugins.

Installation

Install plugin-hooks using npm:

$ npm install plugin-hooks

Create a Plugin

You can create a plugin using one of the following functions:

Create an Asynchronous Plugin

To create an asynchronous plugin, use the createAsyncPlugin function. This function takes two optional parameters which are the initialValue and options.

import { createAsyncPlugin } from 'plugin-hooks';

const plugin = createAsyncPlugin<number, {}>();

The parameters are:

• initialValue (optional): the initial value of the plugin.
• options (optional): an object that contains options for the plugin.

The options object supports the following option:

• returnOnFirst (optional): a boolean value that indicates whether the plugin should return the first fulfilled result instead of continuing

Create a Synchronous Plugin

To create a synchronous plugin, use the createSyncPlugin function. This function takes one optional parameter which is the initialValue.

import { createSyncPlugin } from 'plugin-hooks';

const plugin = createSyncPlugin<any>();

The parameters are:

• initialValue: the initial value of the plugin.

Push Middleware

You can add middleware to the plugin using the pushMiddleware function. This function takes a function as its only parameter.

plugin.pushMiddleware(function times2(val) {
  // do something with the value
});

Dispatch

Once you have added all the middleware you need, you can dispatch the plugin with the dispatch function. This function takes the initialValue as its only parameter and returns the final value will be resolved with the final value.

const r1 = await asyncPlugin.dispatch(1);

Finish Plugin Early

For asynchronous plugins, you can finish the plugin early with the finish function. This function takes a value as its only parameter and immediately resolves the promise.

plugin(function times2(val, _, self) {
  return self.finish(555);
});

For synchronous plugins, you can finish the plugin early with the finish function. This function takes a value as its only parameter.

plugin(function times2(val, _, context) {
  return context.finish(555);
});

Return Initial Value When Without Plugins

If there are no middleware added to the plugin, the initial value will be returned when the dispatch function is called.

const r1 = await plugin.dispatch(1);
expect(r1).toBe(1);

Throw Errors

If an error is thrown in a synchronous plugin, it will be propagated to the dispatch function.

plugin(function times2(val) {
  throw 'foo';
});

expect(() => plugin.dispatch(mutable)).toThrow('foo');