我无法在 socketcluster 的 socket.on 中访问我的变量

Question

我想将 的值分配给msg变量，sample但它无法sample在回调内部访问。

import { Injectable } from '@angular/core';

import * as socketCluster from 'socketcluster-client';

@Injectable({

  providedIn: 'root'

})

export class DatamanagerService {

  socket = socketCluster.create({

    port: 8000

  });

  sample:string;

  constructor() { 

  }

  connect() {

    this.socket.on('connect', function () {

      console.log('CONNECTED');

    });

    this.socket.on('random', function (msg) {

      console.log('RANDOM: ' + msg);

      this.sample = msg; // <- here

    });

  }

}

Answer 1

this上下文，几乎可以肯定。我不完全确定this在socket.onget内部调用的函数将使用什么上下文，但箭头函数使用 lexical this，因此这将是一种解决方案。this.socket.on('random', (msg) => {&nbsp; console.log('RANDOM: ' + msg);&nbsp; this.sample = msg;});