🚀 go-pugleaf

in This script i need to replace single word لا with the same + Hair Space: ~|.

app.findGrepPreferences = app.changeGrepPreferences = null;
app.findGrepPreferences.findWhat = '\bلا\b'
app.changeGrepPreferences.changeTo = 'لا~|'
app.activeDocument.changeGrep();

While nothing happens with the first with the metacharacter \b, the second work good but changes both on single words that other words with the two fianle letters (es: i need to replace be, and no in "be" and "no" word not "be" or "no" in adobe, and in casino, milano, ...)

app.findGrepPreferences = app.changeGrepPreferences = null;
app.findGrepPreferences.findWhat = 'لا '
app.changeGrepPreferences.changeTo = 'لا~|'
app.activeDocument.changeGrep();

لا is an arabic word = No

Does anyone know the proper syntax to get this to work? Thanks!