Comparison of module method declarations

If you're using objects I'd say bar3 is probably best - but if you don't need any state then just export functions rather than a whole object.

If you do:

function Foo(){
  this.bar = bar;
  };

then even once initialised, Espruino will still contain this.bar = bar;, which would be wasting some memory.

The important thing to remember is that Espruino actually executes the module code at the time it is uploaded, so:

function Foo() {
}

Foo.prototype.bar = function() {
};

Is executed, and you end up with effectively:

var Foo = {
  prototype : {
   bar : function() {}
  }
};

So it doesn't actually matter if you manage to take few bytes off the minified module. What matters is the amount of memory that's used (process.memory().usage) after the module has been uploaded - and for that, you want the minimum amount of 'boilerplate' code inside functions.