Iterate through Stories in page order

Hi Robert, Manan was talking about iterating through the whole page collection. Probably is a faster approach than what I proposed in a longer doc too. 

@Andrew24943677v30i 

Without wanting to criticize my colleagues, I strongly discourage the proposed solution (which anyway seems problematic in other respects), simply because commands such that 

a.textContainers[0].parentPage.documentOffset

within a custom sort function will explode the Scripting DOM as soon as the document contains a huge number of stories. In ExtendScript, a custom sort involves on average 5×N×Log(N) internal calls of the function.

Note. - You should also take care of possible runtime errors (e.g. parentPage may be null, etc) and other issues (what about master pages?)

As usual, the solution I suggest is based on generating safe UTF16 sort keys through one linear loop, calling the native Array.prototype.sort() and building the desired array. Safer and probably much faster with long documents.

Here is a quick implementation [not tested in depth but you get the idea]

function sortedStories(/*Document*/doc,  K,ev,r,a,i,t)
{
  // Init.
  const CHR = String.fromCharCode;
  K=doc.stories, ev=K.everyItem(), r=ev.id, a=ev.textContainers;

  // Make sort keys  ->  r[i] :: <key> + storyId
  for
  (
    i=r.length ; i-- ;
    // ---
    (t=a[i]).length              // Have we a container?
    && (t=t[0].parentPage)           // Have we a parent page?
    && 'Spread'===t.parent.constructor.name  // Skip master pages!
    ? ( r[i]=CHR(1+t.documentOffset)+r[i] )  // Make 1st char sortable, add the ID.
    : r.splice(i,1)
  );

  // Instant sort.
  r.sort();

  // Build array of sorted stories and return.
  for( i=r.length ; i-- ; r[i]=K.itemByID(parseInt(r[i].slice(1),10)) );
  return r;
};

var myStories = sortedStories(app.activeDocument);
// etc

[EDIT] Still, this is certainly not the optimal way to reach the goal, but I wanted to illustrate my point while keeping the textContainers[0].parentPage.documentOffset approach proposed by @brian_p_dts 

Best,

Marc