if is not catching... nor does try-catch...

The if (C) {...}-thing still gives me annoying grieve,... I thought the added curly braces would have solved the issue for good...

 1v70 Copyright 2014 G.Williams
>echo(0);
Uncaught Error: FOR loop can only iterate over Arrays, Strings or Objects, not undefined
 at line 1 col 288
...or(var v in C)this.C[v]=C[v]}
                               ^

Related to this code (line 10 in constructor), coming from the (again) working space-only-minified sandbox modules folder. (Had to re-enable some minification option after getting unexplicable out of memory error - see http://forum.espruino.com/comments/11900960/).

// ACD pins for X-, X+, Y-, Y+, optional - but one - callbacks, optional C(onfig) 
function TOUCHR(xn,xp,yn,yp,onDownCB,onTrackCB,onUpCB,onEscCB,C) {
  this.xn = xn; this.xp = xp; this.yn = yn; this.yp = yp;
  this.cbs = [[onDownCB,onTrackCB,onUpCB,onEscCB]]; 
  this.w = null; this.te = 0; this.upCnt = 0; this.up = true;
  this.xr = this.xrr = this.yr = this.yrr = -1;
  this.x = this.x0 = this.x1 = -1;
  this.y = this.y0 = this.y1 = -1;
  this.t = this.t0 = this.t1 =  0;
  if (C) { for (var v in C) { this.C[v] = C[v]; } }
}

The constructor is invoked with undefined for C.

The minification messes with the code to the point where the execution and block nesting becomes broken... Why would I say so: Adding/removing some code further down in the module made the error flip-flop...

Interestingly, when I put a console.log() in the if-(then) block, it 'tricks' the minification and - miraculously (for me) - works:

  if (C) { console.log("C:",C); for (var v in C) { this.C[v] = C[v]; } }

@Gordon, since you know your code like your own pockets, I'm sure you have a nice explanation - and may be - even a remedy top of your head... ;-)

The stuff seems to be related to what @DaveNI experienced in Minified Code Producing Error - Solved at http://forum.espruino.com/conversations/257029/