javascript - 如何避免 Angular observable 中的 "InternalError: too much recursion"？

Question

我有一个简单的 Angular 可观察对象，它应该连续运行，检查每个循环的时间差，并每秒循环一次。当我运行它时，我收到“InternalError:太多递归”。据此:http://bonsaiden.github.io/JavaScript-Garden/#dealing-with-possible-blocking-code 我正在使用正确的方法。如何修复？

Angular 可观察:

export class MyService {
  private lastHeartBeatTime = null; // Time of the last heartbeat
  private heartBeatTimeoutId = null;

  private secondsToHeartbeatAlert = 5; // Number of seconds of no heartbeat 

  constructor() {
    this.lastHeartBeatTime = performance.now(); // Initialise local heartbeat variable with current time
  }

  subscribeToHeartbeat(callbackfn): any {
    // Post a value via the observable to cause an alert to be raised:
    if((performance.now() - this.lastHeartBeatTime) / 1000 >= this.secondsToHeartbeatAlert) return(true);
    // Create a new timeout to call this function again after the specified num of milliseconds (e.g. after 1 second):

    // **** PROBLEM HERE: ***
    else this.heartBeatTimeoutId = setTimeout(this.subscribeToHeartbeat(callbackfn), 1000);
  }
}

另一个组件内的订阅:

// Subscribe to heartbeat over websockets:
MyService.subscribeToHeartbeat(this.handleHeartbeatFailure);

// Handler:
  handleHeartbeatFailure:any = (message) => {
   alert('Websocket is down!")
  }

Answer 1

您正在调用该函数，但没有在超时时间内分配它

setTimeout(this.subscribeToHeartbeat(callbackfn), 1000);

需要

setTimeout(() => this.subscribeToHeartbeat(callbackfn), 1000);

或者你可以使用绑定(bind)

setTimeout(this.subscribeToHeartbeat.bind(this, callbackfn), 1000);