JavaScript How to get value of variable assigned inside Promise onSuccess outside promise

Question

I\'m whiting firefox extension. I got function that\'s reading contents of file:

var HelloWorld = {...
getData: function () {
        var env = Components.classe         


        

Answer 1

getData: function () {
        var env = Components.classes["@mozilla.org/processenvironment;1"].getService(Components.interfaces.nsIEnvironment);
        var path = env.get("TEMP");
        path = path + "\\lastcall.txt"
        alert(path);
        Components.utils.import("resource://gre/modules/osfile.jsm");
        return OS.File.read(path).then(function(array) {
          let decoder = new TextDecoder(); 
          return decoder.decode(array);
        });
    },
...};

Instead of returning line you return promise for line, then the caller can do:

var line = getData();

// When you finally need the actual line, unwrap it:

line.then(function(actualLine) {

});