Question

    websocketstart()
    {
        exampleSocket = new WebSocket('ws://127.0.0.1:8000');
        exampleSocket.onopen = function() {
            // alert('handshake successfully established. May send data now...');
            // exampleSocket.send('hello!!!')
        };
        exampleSocket.onmessage = function(event) {
            let result = JSON.parse(event.data);
            if(result.error == false)
            {
                console.log("ERROR : " + result.parent.message);
                alert('error');
                return;
            }
            this.wantcallfunction(); //<---- SCRIPT438: Object doesn't support property or method 'wantcallfunction'
            return;
        };
        exampleSocket.onclose = function() {
            alert('connection closed');
        };
    }

    wantcallfunction()
    {

    }

this.wantcallfunction（）; // <---- SCRIPT438：对象不支持属性或方法“ wantcallfunction”

还有其他方法可以从onmessage中调用该函数吗？

Answer 1

使用箭头函数，以便将this的上下文保留为类。

更改

exampleSocket.onmessage = function(event) {
    // `this` is not the class

收件人

exampleSocket.onmessage = (event) => {
    // `this` is  the class

Answer 2

static instance : MySocketTest 

MySocketTest.instance = this;

exampleSocket.onmessage = function(event) {
MySocketTest.instance.wantcallfunction();

已解决。

没有错误，但是我不知道这是否正确。

javascript websocket如何在onmessage中调用函数？

2 个答案: