javascript原型函数被忽略

我正在吃晚饭

“无法读取未定义的属性“bind”

我的javascript对象中的问题。如何强制执行绑定

调用此函数时会发生这种情况：

function ViewportDatasource(mockServer) {
        this.mockServer = mockServer;        
        this.connectionId =this.mockServer.connect(this.eventListener.bind(this));
    }

即使在原型函数中正确定义了

eventListener

 ViewportDatasource.prototype.eventListener = function (event) {
        switch (event.eventType) {
            case 'rowCountChanged':
                this.onRowCountChanged(event);
                break;
            case 'rowData':
                this.onRowData(event);
                break;
            case 'dataUpdated':
                this.onDataUpdated(event);
                break;
        }
    };

我能做什么

为了回答Daniel的问题，将在此处调用该实例：

 function setRowData($http) {
        // set up a mock server - real code will not do this, it will contact your
        // real server to get what it needs
        var mockServer = new MockServer();
        $http.get('data.json').then(function(response){
            mockServer.init(response.data);
        });

        var viewportDatasource = new ViewportDatasource(mockServer);
        table.api.setViewportDatasource(viewportDatasource);
        // put the 'size cols to fit' into a timeout, so that the scroll is taken into consideration
        setTimeout(function () {
            table.api.sizeColumnsToFit();
        }, 100);
    }

调用方中的ag grid对象准备就绪后执行此函数

function ViewportDatasource(mockServer) {
    //the this operator here is undefined. function is not of object.
    this.mockServer = mockServer;        
    this.connectionId =this.mockServer.connect(this.eventListener.bind(this));
}

---

只有将函数绑定到对象时，才应使用this运算符，在这种情况下，this运算符才有意义。在上面的例子中没有。

您是如何构造实例的？什么时候？我怎样才能纠正它？那么，我如何引用对象本身呢？