mirror of
https://github.com/idanoo/GoScrobble.git
synced 2024-11-25 09:55:15 +00:00
295 lines
8.4 KiB
Markdown
295 lines
8.4 KiB
Markdown
# Tapable
|
||
|
||
The tapable package expose many Hook classes, which can be used to create hooks for plugins.
|
||
|
||
``` javascript
|
||
const {
|
||
SyncHook,
|
||
SyncBailHook,
|
||
SyncWaterfallHook,
|
||
SyncLoopHook,
|
||
AsyncParallelHook,
|
||
AsyncParallelBailHook,
|
||
AsyncSeriesHook,
|
||
AsyncSeriesBailHook,
|
||
AsyncSeriesWaterfallHook
|
||
} = require("tapable");
|
||
```
|
||
|
||
## Installation
|
||
|
||
``` shell
|
||
npm install --save tapable
|
||
```
|
||
|
||
## Usage
|
||
|
||
All Hook constructors take one optional argument, which is a list of argument names as strings.
|
||
|
||
``` js
|
||
const hook = new SyncHook(["arg1", "arg2", "arg3"]);
|
||
```
|
||
|
||
The best practice is to expose all hooks of a class in a `hooks` property:
|
||
|
||
``` js
|
||
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:
|
||
|
||
``` js
|
||
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:
|
||
|
||
``` js
|
||
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:
|
||
|
||
``` js
|
||
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:
|
||
|
||
``` js
|
||
class Car {
|
||
/* ... */
|
||
|
||
setSpeed(newSpeed) {
|
||
this.hooks.accelerate.call(newSpeed);
|
||
}
|
||
|
||
useNavigationSystemPromise(source, target) {
|
||
const routesList = new List();
|
||
return this.hooks.calculateRoutes.promise(source, target, routesList).then(() => {
|
||
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__. TODO
|
||
|
||
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:
|
||
|
||
``` js
|
||
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.
|
||
|
||
``` js
|
||
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
|
||
|
||
``` js
|
||
const keyedHook = new HookMap(key => new SyncHook(["arg"]))
|
||
```
|
||
|
||
``` js
|
||
keyedHook.tap("some-key", "MyPlugin", (arg) => { /* ... */ });
|
||
keyedHook.tapAsync("some-key", "MyPlugin", (arg, callback) => { /* ... */ });
|
||
keyedHook.tapPromise("some-key", "MyPlugin", (arg) => { /* ... */ });
|
||
```
|
||
|
||
``` js
|
||
const hook = keyedHook.get("some-key");
|
||
if(hook !== undefined) {
|
||
hook.callAsync("arg", err => { /* ... */ });
|
||
}
|
||
```
|
||
|
||
## Hook/HookMap interface
|
||
|
||
Public:
|
||
|
||
``` ts
|
||
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,
|
||
tap: (key: any, name: string | Tap, fn: (context?, ...args) => Result) => void,
|
||
tapAsync: (key: any, name: string | Tap, fn: (context?, ...args, callback: (err, result: Result) => void) => void) => void,
|
||
tapPromise: (key: any, name: string | Tap, fn: (context?, ...args) => Promise<Result>) => void,
|
||
intercept: (interceptor: HookMapInterceptor) => void
|
||
}
|
||
|
||
interface HookMapInterceptor {
|
||
factory: (key: any, hook: Hook) => Hook
|
||
}
|
||
|
||
interface Tap {
|
||
name: string,
|
||
type: string
|
||
fn: Function,
|
||
stage: number,
|
||
context: boolean
|
||
}
|
||
```
|
||
|
||
Protected (only for the class containing the hook):
|
||
|
||
``` ts
|
||
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:
|
||
|
||
``` js
|
||
const { MultiHook } = require("tapable");
|
||
|
||
this.hooks.allHooks = new MultiHook([this.hooks.hookA, this.hooks.hookB]);
|
||
```
|