using c.test in E.showMenu

Btw, I stated in previous post - #6 - that Code_1 survives the minifier... I just checked and it does not! - It fails with the same issue, because - again - the single variable definition of a moves into the then path and if the else path is executed, overwrite of global a still happens... ouch:

Code_1 minified:

move: function(b){
  if(l.selectEdit){
    var a=l.selectEdit;
    a.value-=(b||1)*(a.step||1);
    void 0!==a.min&&a.value<a.min&&(a.value=a.min);
    void 0!==a.max&&a.value>a.max&&(a.value=a.max);
    if(a.onchange)a.onchange(a.value);
    l.draw(options.selected,options.selected)}
  else a=options.selected,options.selected=(b+options.selected)%menuItems.length
     , 0>options.selected&&(options.selected+=menuItems.length)
     , l.draw(Math.min(a,options.selected),Math.max(a,options.selected))
};

A small change though makes a big difference and makes the variable definition to survive the minifier and also already safes 11 bytes....

Code_1.1:

move: function(dir) {
      var item = l.selectEdit,a;
      if (item) {
        item.value -= (dir||1)*(item.step||1);
        if (item.min!==undefined && item.value<item.min) item.value = item.min;
        if (item.max!==undefined && item.value>item.max) item.value = item.max;
        if (item.onchange) item.onchange(item.value);
        l.draw(options.selected,options.selected);
      } else {
        a=options.selected;
        options.selected = (dir+options.selected)%menuItems.length;
        if (options.selected<0) options.selected += menuItems.length;
        l.draw(Math.min(a,options.selected), Math.max(a,options.selected));
      }
    };

Code_1.1 minified:

move: function(b){
  var a=l.selectEdit;
  if(a){
    a.value-=(b||1)*(a.step||1);
    void 0!==a.min&&a.value<a.min&&(a.value=a.min);
    void 0!==a.max&&a.value>a.max(a.value=a.max);
    if(a.onchange)a.onchange(a.value);
    l.draw(options.selected,options.selected)}
  else a=options.selected
     , options.selected(b+options.selected)%menuItems.length
     , 0>options.selected&&(options.selected+=menuItems.length)
     , l.draw(Math.min(a,options.selected),Math.max(a,options.selected))
};

Very interesting.

The whole thing comes form JS var behavior introduced by the compile into byte code / the way byte code is generated: Any encountered var in a var-scoped block (function) moves the declaration IN THE BYTE CODE 'up' to be processed before the first execution statement... See Variable Hoisting - https://www.sitepoint.com/demystifying-javascript-variable-scope-hoisting/. The regular minifier is based on that behavior, takes advantage of it, and sees no issue with it. After all minification is the goal... compiler/byte code generation will take care of proper sequencing.

Espruino does no hoisting... it sticks to the sequence by its very own and unique nature... (see https://www.espruino.com/Features#general).