writing a simple helper module

The plan is to write a module and include it in custom build with JSMODULESOURCES to have all nice tools in place without wasting time on load.

Starting with a time helper as sample, I was fiddling around and have no clue how to write a working module. Any suggestions how to make this work?

// module code  jstools.js

var jstools = function (){};

jstools.prototype.setTimeByUrl = function(url,tz,callback) {
	require('http').get(url, function(res){
    	var date = new Date(res.headers.Date);
    	if (date > 0 ) {
      		setTime(date/1000);
      		E.setTimeZone(tz);
      		error = null;
    	} else {
      		error = 'no date';
  		}
  		if (callback)
  			callback(error);
	});
};

exports = jstools;

// test code 
var jstools = require('jstools');

setTimeout(function(){
  jstools.setTimeByUrl('http://www.espruino.com',1,function(e){console.log(e);});
},1000);

//output 
Uncaught Error: Function "setTimeByUrl" not found!
 at line 1 col 9
jstools.setTimeByUrl('http://www.espruino.com',1,function(e)...
        ^
in function called from system
 

Hmm first guess is you need to create an instance of your jstools "class" with new.

var JsTools = require('jstools');

var jt = new JsTools();

setTimeout(function() {
    jt.setTimeByUrl('http://www.espruino.com', 1, console.log);
}, 1000);

Not tested... but should work :)

thanks for your suggestion, this is the output

Uncaught Error: Function "setTimeByUrl" not found!
at line 1 col 4
jt.setTimeByUrl('http://www.espruino.com', 1, console.log);
^
in function called from system

Oh i made a mistake.. try to change the require statement to this..

var JsTools = require('./jstools');

If the module is in the same directory of course. Important point is to provide the path (absolut or relative) to the module.

Thanks, just got it.

just export each function and that's it.

// module jtools.js
exports.setTimeByUrl = function(url,tz,callback) {
	require('http').get(url, function(res){
    	var date = new Date(res.headers.Date);
    	if (date > 0 ) {
      		setTime(date/1000);
      		E.setTimeZone(tz);
      		error = null;
    	} else {
      		error = 'no date';
  		}
  		if (callback)
  			callback(error);
        });
};

// test module jtools.js
var jt = require('jstools');
jt.setTimeByUrl('http://www.espruino.com',1,function(e){console.log(e);});

and no more erros :)

Exporting each function removes the need to instantiate with new but should not change the mistake i made with the require. Very Strange.. but glad it works now :)

The require('jstools') works because working with the WebIDE and store the jstools.js file in the module directory of my working project.

Ah this explains it.. i develop my modules in a IDE and serve them via a server on localhost.
Then i require them via URL when i want to test them in the WebIDE.

There's some info on making modules here: http://www.espruino.com/Writing+Modules

It's for the website, but that way of working can go equally well when trying to build a module in.

But yes, the main thing is anything you want to access directly should just be exports.xyz = ....

One other thing to note: If you're trying to do arrays in a built-in module, try and do them inside a function where possible:

exports.getMyArray = function() { return [....] }; stores the function text in flash until it's executes, but exports.myArray = [....]; will put the array in RAM as soon as you first call require(...) and will keep it there