Need a quick help on this (JS)

General
1

I mapped the Parameter Observable to get a value but the variable used in storing the value didn’t work in the same JS file. Like this

      var number = this.Parameter.map(function(param){return param.user_number;})

and I tried using variable number in a function in the same JS file like this ;

      function show(){
          var sql = db.query('select * from result where matric_no = ?', number);
          debug_log(JSON.stringify(sql));
          debug_log(matric_no)
      }

but I keep getting [] and Fuse.Scripting.V8.Object

2

If you’re calling the show() function before the derived number Observable is populated, you might not be getting any value there. It’s populated asynchronously.

As for the Fuse.Scripting.V8.Object, you can do this: console.log(JSON.stringify(matric_no)) to see what’s inside complex structures.

3

Here is what’s inside

  {"_subscribers":[null],"_isLeaf":false,"_values":["2014235020035"]}

How do I access that number there in?

4

Since you’re asking about an Observable, why don’t you first go and give Observable docs a thorough read?

You really need to start posting complete, minimal reproductions. There is no good way for anyone to answer “how do I access X” without seeing what you do to “X” and where it comes from.

Disclaimer: a complete, minimal reproductions == single-UX-file app that one can copy-paste and run.

5

Here is where the data is coming from (SplashPage.js)

  var Observable = require('FuseJS/Observable');
  var matric_no = Observable('');
  var password = Observable('');

 function Login(arg){

   var r = '';
   var std_matric = arg.data.matric_no.value;
   var std_pass = arg.data.password.value;

      if(std_pass == '' || std_matric == ''){
	   debug_log('Enter matric/password');
	   //error_empty.value = true;
       }

           r = db.query('select * from student where matric_no = ? and user_password = ?',std_matric,std_pass);
         if(r != ''){
	    router.goto('home',r[0]);
         }else{
	    debug_log('Incorrect Login Details');
	    //error_flag.value = true;
       }		
      }

   module.exports = {
      Login:Login,
      matric_no:matric_no,
      password:password
     }

Here is the Home.js

   var student = this.Parameter;
   var sqlite = require('SQLite');
   var db = sqlite.openFromBundle('db.sqlite');
   var matric_no = this.Parameter.map(function(param){return param.matric_no});

      function show_result(args){
             var name = args.data.name;
             var semester = args.data.value;
             var sql = db.query('select * from result where matric_no = ?',matric_no);
                     debug_log(JSON.stringify(matric_no));
                     debug_log(matric_no);

       }
       module.exports = {
          matric_no:matric_no,
          show_result:show_result
        }

Here is the full code, the value of the matric_no variable is not accessible in the show_result() function.

6

That is not a complete, minimal reproduction - I can not copy&paste and run it. The keyword is “complete” in this case.

Let me repeat myself: If you’re calling the show_result() function before the derived matric_no Observable is populated, you might not be getting any value there. It’s populated asynchronously.

And again: Since you’re asking about an Observable, why don’t you first go and give Observable docs a thorough read?

7

I have updated the code, please try look into it. I just need to access the matric_no variable in other functions after the Observable(this.Parameter) mapping.

8

I have gone through that a quite number of times, my answer is not just there I think.

9

That is still not a complete, minimal reproduction. Your sqlite query might be failing, you might be calling show_result() function before the derived Observable is populated etc. There is no way to help you with the bits of code you’re showing.

10

There is nothing I can paste any longer, you helped me with that sqlite query some days ago and they routing and also working fine, the only problem is that I can not access the values of the variables I retrieved from the Parameter in the same JS file.

I need this variable (matric_no) of the code:

  var matric_no = this.Parameter.map(function(param){return param.matric_no});

to be accessible in the same file but it’s returning a Fuse.V8.Scripting.object instead of the number ‘2014235020035’ as seen in the debug_log(JSON_stringify(matric_no))

11

It is an Observable, so it is perfectly fine that it’s Fuse.Scripting.V8.Object.

Derived Observables are populated asynchronously, as I explained a couple posts ago. Plus, they are only calculated if they are consumed, that is - they have at least one subscriber. Since you have added matric_no to your module.exports, it suggests that there, indeed, is a subscription to it. However, I don’t see that because you’re not showing how you use it in UX!

It’s all explained in Observable docs.

Try changing your Home.js to this:

   var student = this.Parameter;
   var sqlite = require('SQLite');
   var db = sqlite.openFromBundle('db.sqlite');
   var matric_no = this.Parameter.map(function(param){return param.matric_no});
   matric_no.subscribe(module);

      function show_result(args){
             var name = args.data.name;
             var semester = args.data.value;
             var sql = db.query('select * from result where matric_no = ?',matric_no.value);
             debug_log(matric_no.value);
       }
       module.exports = {
          matric_no:matric_no,
          show_result:show_result
        }

So once again: there is absolutely no way to help you if you’re not sharing COMPLETE reproductions. And “there is nothing I can paste any longer” is just a false statement. Yes, you can. You need to prepare a minimal repro that includes both UX and JS code, and holds that in a single-UX-file app.

12

Okay. I really appreciate this. Thanks a lot. It has worked, you are a geek.