In the previous episode we learned that every scripting DOM object is in fact an object specifier, which acts like a path in the InDesign object tree. Collection's methods only allow us to build object specifiers. Invoking a property or a method provided by a specifier causes InDesign to send a “verb-first command” to the underlying receiver(s). We will now consider how this process impacts your code, what is returned into your script and how to deal with some side effects.
Tips
Scripter corner: howtos, tips and tricks (InDesign Javascript).On ‘everyItem()’ – Part 1
June 30, 2010 | Tips | en
Every collection in the scope of the InDesign Scripting DOM provides a method called everyItem. It remained undocumented until InDesign CS3, but scripting experts such as Dave Saunders had already pointed out its forcefulness and already knew how to exploit it. Here are some details about this esoteric syntax.
Operator Overloading with ExtendScript
May 25, 2010 | Tips | en
Operator overloading in JavaScript is a controversial issue. Actually, this dangerous feature has been rejected in ECMAScript 4. However, ExtendScript allows you to override the behavior of many mathematical and logical operators on a class-by-class basis since CS2.
Binary JavaScript Embedment (CS4/CS5)
April 13, 2010 | Tips | en
The jsxbin format (“Binary JavaScript”) is a boon for developers because it enables them to distribute a script without exposing its precious code. The ExtendScript ToolKit (ESTK) offers an Export to Binary feature which instantly converts a human-readable js(x) file into jsxbin. InDesign can then interpret this file as if it were a pure JavaScript. The only (boring!) problem is that the encoded script is not allowed to load a persistent session through the #targetengine directive. Here is a secret trick to bypass this limitation with a single encrypted file.
Can InDesign Script Rewrite Itself?
November 06, 2009 | Tips | en | fr
As illustrated by the YALT technique, it's easy —and powerful!— to let a script read its own bytes while it is running. We could even go further and get a script to update itself to achieve some advanced functionalities.
Work Around the Width/Height Gap
October 17, 2009 | Tips | en
Believe me or not, the InDesign DOM can't return directly the width and the height of a page item frame! Scripting beginners may be confused about this gap. There are many pitfalls to be aware of when we deal with dimensions and units. Let's talk about bounds and coordinate spaces...
How to Quickly Test a Sample Code
June 10, 2009 | Tips | en | fr
Sometimes you just need to test a short snippet without having to create and install a complete script. Suppose you want to check some object properties, or to evaluate a simple JavaScript expression. It is easy to write and interprete your instructions from the ExtendScript Toolkit, but it would be even faster to do the whole job from the InDesign user interface.
Type your Code
JavaScript is often considered as a weakly typed language. It means —among other things— that we don't need to tell explicitly what kind of variables we handle, or what kind of arguments we provide to a given function. String? Integer? Boolean? In most cases, everything will work without ever declaring the type.
