Socket
Socket
Sign inDemoInstall

tapable

Package Overview
Dependencies
0
Maintainers
1
Versions
48
Alerts
File Explorer

Advanced tools

Install Socket

Detect and block malicious and high-risk dependencies

Install

    tapable

Just a little module for plugins.


Version published
Maintainers
1
Install size
46.7 kB
Created

Package description

What is tapable?

The tapable package provides a collection of classes that can be used to add hooks into a plugin system. These hooks can be used to intercept and modify the behavior of certain functions or events, allowing for a highly customizable and extensible architecture. It is commonly used in webpack's plugin system but can be used in any JavaScript project to add similar plugin capabilities.

What are tapable's main functionalities?

SyncHook

SyncHook allows for synchronous execution of multiple functions. It is useful when you need to ensure that hooks are executed in the order they were added.

const { SyncHook } = require('tapable');

const hook = new SyncHook(['arg1', 'arg2']);

hook.tap('MyPlugin', (arg1, arg2) => {
  console.log(`Values received: ${arg1}, ${arg2}`);
});

hook.call('Hello', 'World');

AsyncParallelHook

AsyncParallelHook allows for asynchronous execution of hooks in parallel. It is useful when you have multiple asynchronous tasks that can run at the same time without waiting for each other.

const { AsyncParallelHook } = require('tapable');

const asyncHook = new AsyncParallelHook(['arg1']);

asyncHook.tapPromise('AsyncPlugin', (arg1) => {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      console.log(`Async value: ${arg1}`);
      resolve();
    }, 1000);
  });
});

asyncHook.promise('Hello').then(() => {
  console.log('All async plugins have finished.');
});

AsyncSeriesHook

AsyncSeriesHook allows for asynchronous execution of hooks one after another. It is useful when tasks need to be done in a specific sequence, with each task starting only after the previous one has completed.

const { AsyncSeriesHook } = require('tapable');

const asyncSeriesHook = new AsyncSeriesHook(['arg1']);

asyncSeriesHook.tapPromise('AsyncSeriesPlugin', (arg1) => {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      console.log(`Async series value: ${arg1}`);
      resolve();
    }, 1000);
  });
});

asyncSeriesHook.promise('World').then(() => {
  console.log('All async series plugins have finished.');
});

Other packages similar to tapable

Readme

Source

Tapable

The tapable package expose many Hook classes, which can be used to create hooks for plugins.

const {
	SyncHook,
	SyncBailHook,
	SyncWaterfallHook,
	SyncLoopHook,
	AsyncParallelHook,
	AsyncParallelBailHook,
	AsyncSeriesHook,
	AsyncSeriesBailHook,
	AsyncSeriesWaterfallHook
 } = require("tapable");

Installation

npm install --save tapable

Usage

All Hook constructors take one optional argument, which is a list of argument names as strings.

const hook = new SyncHook(["arg1", "arg2", "arg3"]);

The best practice is to expose all hooks of a class in a hooks property:

class Car {
	constructor() {
		this.hooks = {
			accelerate: new SyncHook(["newSpeed"]),
			brake: new SyncHook(),
			calculateRoutes: new AsyncParallelHook(["source", "target", "routesList"])
		};
	}

	/* ... */
}

Other people can now use these hooks:

const myCar = new Car();

// Use the tap method to add a consument
myCar.hooks.brake.tap("WarningLampPlugin", () => warningLamp.on());

It's required to pass a name to identify the plugin/reason.

You may receive arguments:

myCar.hooks.accelerate.tap("LoggerPlugin", newSpeed => console.log(`Accelerating to ${newSpeed}`));

For sync hooks, tap is the only valid method to add a plugin. Async hooks also support async plugins:

myCar.hooks.calculateRoutes.tapPromise("GoogleMapsPlugin", (source, target, routesList) => {
	// return a promise
	return google.maps.findRoute(source, target).then(route => {
		routesList.add(route);
	});
});
myCar.hooks.calculateRoutes.tapAsync("BingMapsPlugin", (source, target, routesList, callback) => {
	bing.findRoute(source, target, (err, route) => {
		if(err) return callback(err);
		routesList.add(route);
		// call the callback
		callback();
	});
});

// You can still use sync plugins
myCar.hooks.calculateRoutes.tap("CachedRoutesPlugin", (source, target, routesList) => {
	const cachedRoute = cache.get(source, target);
	if(cachedRoute)
		routesList.add(cachedRoute);
})

The class declaring these hooks need to call them:

class Car {
	/**
	  * You won't get returned value from SyncHook or AsyncParallelHook,
	  * to do that, use SyncWaterfallHook and AsyncSeriesWaterfallHook respectively
	 **/

	setSpeed(newSpeed) {
		// following call returns undefined even when you returned values
		this.hooks.accelerate.call(newSpeed);
	}

	useNavigationSystemPromise(source, target) {
		const routesList = new List();
		return this.hooks.calculateRoutes.promise(source, target, routesList).then((res) => {
			// res is undefined for AsyncParallelHook
			return routesList.getRoutes();
		});
	}

	useNavigationSystemAsync(source, target, callback) {
		const routesList = new List();
		this.hooks.calculateRoutes.callAsync(source, target, routesList, err => {
			if(err) return callback(err);
			callback(null, routesList.getRoutes());
		});
	}
}

The Hook will compile a method with the most efficient way of running your plugins. It generates code depending on:

  • The number of registered plugins (none, one, many)
  • The kind of registered plugins (sync, async, promise)
  • The used call method (sync, async, promise)
  • The number of arguments
  • Whether interception is used

This ensures fastest possible execution.

Hook types

Each hook can be tapped with one or several functions. How they are executed depends on the hook type:

  • Basic hook (without “Waterfall”, “Bail” or “Loop” in its name). This hook simply calls every function it tapped in a row.

  • Waterfall. A waterfall hook also calls each tapped function in a row. Unlike the basic hook, it passes a return value from each function to the next function.

  • Bail. A bail hook allows exiting early. When any of the tapped function returns anything, the bail hook will stop executing the remaining ones.

  • Loop. When a plugin in a loop hook returns a non-undefined value the hook will restart from the first plugin. It will loop until all plugins return undefined.

Additionally, hooks can be synchronous or asynchronous. To reflect this, there’re “Sync”, “AsyncSeries”, and “AsyncParallel” hook classes:

  • Sync. A sync hook can only be tapped with synchronous functions (using myHook.tap()).

  • AsyncSeries. An async-series hook can be tapped with synchronous, callback-based and promise-based functions (using myHook.tap(), myHook.tapAsync() and myHook.tapPromise()). They call each async method in a row.

  • AsyncParallel. An async-parallel hook can also be tapped with synchronous, callback-based and promise-based functions (using myHook.tap(), myHook.tapAsync() and myHook.tapPromise()). However, they run each async method in parallel.

The hook type is reflected in its class name. E.g., AsyncSeriesWaterfallHook allows asynchronous functions and runs them in series, passing each function’s return value into the next function.

Interception

All Hooks offer an additional interception API:

myCar.hooks.calculateRoutes.intercept({
	call: (source, target, routesList) => {
		console.log("Starting to calculate routes");
	},
	register: (tapInfo) => {
		// tapInfo = { type: "promise", name: "GoogleMapsPlugin", fn: ... }
		console.log(`${tapInfo.name} is doing its job`);
		return tapInfo; // may return a new tapInfo object
	}
})

call: (...args) => void Adding call to your interceptor will trigger when hooks are triggered. You have access to the hooks arguments.

tap: (tap: Tap) => void Adding tap to your interceptor will trigger when a plugin taps into a hook. Provided is the Tap object. Tap object can't be changed.

loop: (...args) => void Adding loop to your interceptor will trigger for each loop of a looping hook.

register: (tap: Tap) => Tap | undefined Adding register to your interceptor will trigger for each added Tap and allows to modify it.

Context

Plugins and interceptors can opt-in to access an optional context object, which can be used to pass arbitrary values to subsequent plugins and interceptors.

myCar.hooks.accelerate.intercept({
	context: true,
	tap: (context, tapInfo) => {
		// tapInfo = { type: "sync", name: "NoisePlugin", fn: ... }
		console.log(`${tapInfo.name} is doing it's job`);

		// `context` starts as an empty object if at least one plugin uses `context: true`.
		// If no plugins use `context: true`, then `context` is undefined.
		if (context) {
			// Arbitrary properties can be added to `context`, which plugins can then access.
			context.hasMuffler = true;
		}
	}
});

myCar.hooks.accelerate.tap({
	name: "NoisePlugin",
	context: true
}, (context, newSpeed) => {
	if (context && context.hasMuffler) {
		console.log("Silence...");
	} else {
		console.log("Vroom!");
	}
});

HookMap

A HookMap is a helper class for a Map with Hooks

const keyedHook = new HookMap(key => new SyncHook(["arg"]))
keyedHook.for("some-key").tap("MyPlugin", (arg) => { /* ... */ });
keyedHook.for("some-key").tapAsync("MyPlugin", (arg, callback) => { /* ... */ });
keyedHook.for("some-key").tapPromise("MyPlugin", (arg) => { /* ... */ });
const hook = keyedHook.get("some-key");
if(hook !== undefined) {
	hook.callAsync("arg", err => { /* ... */ });
}

Hook/HookMap interface

Public:

interface Hook {
	tap: (name: string | Tap, fn: (context?, ...args) => Result) => void,
	tapAsync: (name: string | Tap, fn: (context?, ...args, callback: (err, result: Result) => void) => void) => void,
	tapPromise: (name: string | Tap, fn: (context?, ...args) => Promise<Result>) => void,
	intercept: (interceptor: HookInterceptor) => void
}

interface HookInterceptor {
	call: (context?, ...args) => void,
	loop: (context?, ...args) => void,
	tap: (context?, tap: Tap) => void,
	register: (tap: Tap) => Tap,
	context: boolean
}

interface HookMap {
	for: (key: any) => Hook,
	intercept: (interceptor: HookMapInterceptor) => void
}

interface HookMapInterceptor {
	factory: (key: any, hook: Hook) => Hook
}

interface Tap {
	name: string,
	type: string
	fn: Function,
	stage: number,
	context: boolean,
	before?: string | Array
}

Protected (only for the class containing the hook):

interface Hook {
	isUsed: () => boolean,
	call: (...args) => Result,
	promise: (...args) => Promise<Result>,
	callAsync: (...args, callback: (err, result: Result) => void) => void,
}

interface HookMap {
	get: (key: any) => Hook | undefined,
	for: (key: any) => Hook
}

MultiHook

A helper Hook-like class to redirect taps to multiple other hooks:

const { MultiHook } = require("tapable");

this.hooks.allHooks = new MultiHook([this.hooks.hookA, this.hooks.hookB]);

FAQs

Last updated on 13 Sep 2021

Did you know?

Socket for GitHub automatically highlights issues in each pull request and monitors the health of all your open source dependencies. Discover the contents of your packages and block harmful activity before you install or update your dependencies.

Install

Related posts

SocketSocket SOC 2 Logo

Product

  • Package Alerts
  • Integrations
  • Docs
  • Pricing
  • FAQ
  • Roadmap

Stay in touch

Get open source security insights delivered straight into your inbox.


  • Terms
  • Privacy
  • Security

Made with ⚡️ by Socket Inc