fun-hooks/index.d.ts

A generalized and simple hooking API for adding extensibility to applications

import { Tail, Reverse } from "typescript-tuple";

type Fn = (...args: any) => any;

type RemoveLast<T extends any[]> = Reverse<Tail<Reverse<T>>>;

type Last<T extends any[]> = T[Exclude<keyof T, keyof Tail<T>>];

type LastParameter<F extends (...args: any) => any> = Last<Parameters<F>>;

export interface BeforeSync<T extends Fn> {
  (...args: Parameters<T>): void;
  bail: (returnValue: ReturnType<T>) => void;
}

export interface BeforeAsync<T extends Fn, Cb extends Fn> {
  (...args: RemoveLast<Parameters<T>>): void;
  bail: (...args: Parameters<Cb>) => void;
}

export interface BeforeAsyncNoCallback<T extends Fn> {
  (...args: Parameters<T>): void;
}

export interface AfterSync<T extends Fn> {
  (returnValue: ReturnType<T>): void;
  bail: (returnValue: ReturnType<T>) => void;
}

export interface AfterAsync<T extends Fn> {
  (...args: Parameters<T>): void;
  bail: (...args: Parameters<T>) => void;
}

export interface HookGetter {
  getHooks(
    matcher?:
      | {
          type: "before" | "after";
        }
      | {
          hook: Fn;
        }
  ): Array<Fn> & {
    remove(): void;
  };
  removeAll(): void;
}

export type SyncHook<T extends Fn> = T &
  HookGetter & {
    before: (
      hook: (next: BeforeSync<T>, ...args: Parameters<T>) => void,
      priority?: number
    ) => SyncHook<T>;
    after: (
      hook: (next: AfterSync<T>, returnValue: ReturnType<T>) => void,
      priority?: number
    ) => SyncHook<T>;
  };

export type AsyncHook<T extends Fn> = LastParameter<T> extends Fn
  ? AsyncHookCallback<T, LastParameter<T>>
  : AsyncHookNoCallback<T>;

export type AsyncHookCallback<T extends Fn, Cb extends Fn> = T &
  HookGetter & {
    before: (
      hook: (
        next: BeforeAsync<T, Cb>,
        ...args: RemoveLast<Parameters<T>>
      ) => void,
      priority?: number
    ) => AsyncHookCallback<T, Cb>;
    after: (
      hook: (next: AfterAsync<Cb>, ...args: Parameters<Cb>) => void,
      priority?: number
    ) => SyncHook<T>;
  };

export type AsyncHookNoCallback<T extends Fn> = T &
  HookGetter & {
    before: (
      hook: (next: BeforeAsyncNoCallback<T>, ...args: Parameters<T>) => void,
      priority?: number
    ) => AsyncHookNoCallback<T>;
  };

export interface CreateHook {
  <T extends Fn>(fn: T): SyncHook<T>;
  <T extends Fn>(type: "sync", fn: T, name?: string): SyncHook<T>;
  <T extends Fn>(type: "async", fn: T, name?: string): AsyncHook<T>;
  <Hooks extends { [key: string]: any }, T extends object = object>(
    obj: T,
    props: string[],
    name?: string
  ): Hooks;
  get<T>(name: string): T;
}

export interface HooksFactory {
  (config?: { ready?: number }): CreateHook;
  SYNC: 1;
  ASYNC: 2;
  QUEUE: 4;
}

declare const funHooks: HooksFactory;

export default funHooks;