JS CS3: Help to reduce running time of my script

Question

Hi
We have developed a script to find similiar words/characters at the end/start of 3 or more continous lines. The script has been developed by following steps:
1. Get all lines of the document;
2. Get first 2 characters of first line and compare with next two lines' first 2 characters.
3. If matches, then give a no break before the word to flow.
The same procedure for find end characters of the lines.
As our documents has more than 300 pages, the script runs too long time (about 15 minutes) per document.
Could any suggest to reduce the time of script running?
My basic sript is:
for (k=0; k<myStory.paragraphs.item(i).lines.length; k++) {
var myParaText =  myStory.paragraphs.item(i);
var myChar2Fa = myParaText.lines[k].characters.itemByRange(0,1).texts[0].contents;
var myChar2Fb = myParaText.lines[k+1].characters.itemByRange(0,1).texts[0].contents;
var myChar2Fc = myParaText.lines[k+2].characters.itemByRange(0,1).texts[0].contents;
if (myChar2Fa== myChar2Fb && myChar2Fa== myChar2Fc) {
    myParaText.lines[k+2].characters[-1].noBreak=true;
Kindly suggest.
regards
Masthan

Answer 1

Every interaction with the Object model costs -- in this case, asking ID for paragraphs.item(i).line, itemByrange(), etc. Avoid this by storing as much as possible direct references into variables.
Every interaction with the document text itself also costs -- you will see the script runs much faster if you only count the number of occurrences. (But this cannot be avoided.)
That said, your way of retrieving the first 2 characters per line is rather clumsy ... My version still takes the odd minute or so, for a 300 page test document, but I think it's mainly because ID has to re-flow each paragraph it changes.
myStory = app.selection[0].parentStory;
ln = myStory.lines;
n_ln = ln.length;
for (i=0; i<n_ln-2; i++)
if (ln[i].length > 1 &&
  ln[i].contents.substring(0,2) == ln[i+1].contents.substring(0,2) &&
  ln[i].contents.substring(0,2) == ln[i+2].contents.substring(0,2))
  ln[i+2].characters[-1].noBreak=true;
I'm not convinced this does what you intend: avoiding three consecutive lines to start with the same two characters. First of all, to be sure you'd need to run it again, since reflowing the text may move another word to the front of the line with those same characters.
Second: the [-1] is a special index in InDesign. It does not point to the item before the current (as it would if -1 was treated the same as 0, 1, and 100), but instead it counts backwards from the end of the indexed item -- in this case, the No Break is applied to the last character of the 3rd line. I bet you wanted to apply it to the last character of the 2nd line (which, if so, is easy fixed).