如何在Javascript类中的另一个方法内调用一个方法？

Question

How do you properly call a method inside another method in a JavaScript class?

export class XMLLoader{

constructor(){



}

// Processes the XML request, i.e retrieves the relevant data etc.
 processXMLReq(xhttp){

    let resultXML = xhttp.responseXML;
    let resultText = xhttp.responseText;


    console.log("The result is: " + resultXML);
    console.log("The result is: " + resultText);

    let x = resultXML.getElementsByTagName("road")[0].childNodes[0].nodeValue;


    console.log("The first 'road' node value is: " + x);

}

loadXMLDoc(url){

    let xhttp = new XMLHttpRequest();

    xhttp.onreadystatechange = function(){
        if(this.readyState === 4 && this.status === 200){
            this.processXMLReq(xhttp);
        }

    };

    xhttp.open("GET", url, true);       // the argument "true" means that the request will be executed in async
    xhttp.send();

}

};

As you can see I'm trying to call processXMLReq() inside loadXMLDoc(), why is this not working. Only way I have made it to work is by putting processXMLReq inside the constructor and making it static. This class is supposed to be a utility class for a searchbar class. How can I make it so that I can call processXMLReq inside loadXMLDoc. Because inside my searchbar class I just want to do something like this:

componentDidMount(){

  //  let xmlLoader = new XMLLoader();

    let xmlLoader = new XMLLoader();

    xmlLoader.loadXMLDoc('someURL', this.processXMLReq);


}

Answer 1

Static methods aren't accessed with 'this' they are accessed from the constructor or the classname:

XMLLoader.processXMLReq(data);

or

XMLLoader.constructor.processXMLReq(data);

Answer 2

XMLLoader. processXMLreq(xhttp) because it is a static method