In react, I define a function but it's appear undefine - node.js

Question

I defined a function, but it's undefined in the reference precess. I tried to add breakpoints, the results show that it is a function, but continues to perform an error again, you mean form the callback?
That's the part I quoted, prompt requestServer is not the function, but it has been defined in the code below, the reason why I don't know whether the callback
import React, {Component, PropTypes} from 'react';
import GLogin from './Login';
var serverMethon = require('../../server/requestServer');
export default class LoginContainer extends Component {
constructor(props) {
super(props);
this.state = {
}
}
getLogin = (value) => {
const {selectView} = this.props;
const requestServer = serverMethon.requestServer;
requestServer('login', value, function(t) {
const data = JSON.parse(t.text);
if (data.state != "successful") {
alert("Login fail!")
return;
}
selectView('SearchContainer');
})();
}
render() {
return (
<GLogin
getLogin={this.getLogin}
{...this.props}/>
)
}
}
Function definitions section
var superagent = require('superagent');
export const requestServer = (position, info, callback) => {
superagent.post(`http://localhost:3000/${position}`)
.send(info)
.end((error, doc)=>{
if(error){
throw error
}
callback(doc)
})
}

Answer 1

// proper way
class App extends React.Component{
constructor (props){
super(props);
this.sampleMethod = this.sampleMethod.bind(this);
}
sampleMethod(){
console.log('Sample method called');
}
render(){
return <button onClick={this.sampleMethod}>Click Me</buttom>
}
}
Your mistake is you called your method as this.getLogin. But you don't bind the method. So you can't use this method with this.getLogin. You can use getLogin method without binding. This time you called the method by getLogin but you get context inside getLogin method the context is not be your component. At the time your context is window so you get window object.
So first bind your method then use it.
// your mistake
getLogin = (value)=>{
// your logic
}
// proper way
getLogin(value){
// your logic
}