@player-ui/player/src/logger/tapableLogger.ts

import { SyncHook } from "tapable-ts";
import type { Logger, Severity } from "./types";

/** A logger that has a tapable subscriptions to callbacks */
export default class TapableLogger implements Logger {
  public readonly hooks = {
    trace: new SyncHook<[Array<any>]>(),
    debug: new SyncHook<[Array<any>]>(),
    info: new SyncHook<[Array<any>]>(),
    warn: new SyncHook<[Array<any>]>(),
    error: new SyncHook<[Array<any>]>(),
    log: new SyncHook<[Severity, Array<any>]>(),
  };

  private logHandlers: Set<Logger> = new Set();

  private createHandler(severity: Severity): (...args: any[]) => void {
    return (...args: any[]) => {
      this.hooks[severity].call(args);
      this.hooks.log.call(severity, args);
      this.logHandlers.forEach((logger) => logger[severity](...args));
    };
  }

  public addHandler(logHandler: Logger) {
    this.logHandlers.add(logHandler);
  }

  public removeHandler(logHandler: Logger) {
    this.logHandlers.delete(logHandler);
  }

  public readonly trace = this.createHandler("trace");
  public readonly debug = this.createHandler("debug");
  public readonly info = this.createHandler("info");
  public readonly warn = this.createHandler("warn");
  public readonly error = this.createHandler("error");
}