Regex defined outside of for loop not working?

Question

Long time user, first time asker; very new to regular expressions. I'm a designer trying to make my life in InDesign easier, so please be patient if this is an easy one :) I'm working on a script that pulls pages out of a master file into a template file. Some of these master pages have layers that are to be used when the final file is exported to PDF for print; other layers are to be used when the final file is exported to e-mailing. So, if someone checks an option to save for e-mailing, I want the print layers to hide and the e-mail layers to show. Easy enough, but I wanted to streamline the code as a function so I could specify "print" or "email" as a variable, and then the script would match that to any variable that has "print" in it. Regex territory. var openDocument = app.documents.item(0); var LayerLength = openDocument.layers.length; wordToMatch = "print"; for (i=0;i<LayerLength;i++) { myRegEx = new RegExp(wordToMatch,"i"); str = openDocument.layers.item(i).name; if (str.search(myRegEx) >= 0) { openDocument.layers.item(i).visible = true; } } So, this actually works. It does what I want it to do (Haven't put it in a function yet but I'll get there). It finds layers with "print" in them and then makes them visible. This didn't seem ideal to me, though. I thought it would make more sense to define the regex once and then use it multiple times in the for loop, as follows: wordToMatch = "print"; myRegEx = new RegExp(wordToMatch,"i"); for (i=0;i<LayerLength;i++) { str = openDocument.layers.item(i).name; if (str.search(myRegEx) >= 0) { openDocument.layers.item(i).visible = true; } } But this only does what it's supposed to do on the first layer, then it's unable to match any subsequent layers. Why is this? I feel like I'm misunderstanding something fundamental here, and I'd like to know what that is. Thanks, Brendan

Answer 1

Hi Brendan,

The first thing I'd do to trouble shoot this is actually just take the JavaScript code out and run it separate from InDesign, which you can see run here: https://replit.com/@cmcculloh/MintcreamOrdinaryPreprocessor#index.js

const layers = [

{ name: "bob", visible: false },

{ name: "print", visible: false },

{ name: "print", visible: false },

{ name: "do-not-print", visible: false },

{ name: "print", visible: false },

{ name: "print", visible: false },

];

const wordToMatch = "print";

const myRegEx = new RegExp(wordToMatch, "i");

for (let i = 0; i < layers.length; i++) {

let str = layers[i].name;

if (str.search(myRegEx) >= 0) {

layers[i].visible = true;

}

}

console.log(layers);

This code outputs the following:

[

{ name: 'bob', visible: false },

{ name: 'print', visible: true },

{ name: 'print', visible: true },

{ name: 'do-not-print', visible: true },

{ name: 'print', visible: true },

{ name: 'print', visible: true }

]

This not only will let you see that there is nothing wrong with your Regex/loop (as far as JS is concerned), but also you can see an edge-case/bug you might not have considered.

It appears to me that this is actually an Indesign specific issue and not actually an issue with JS/Regex.

Where I'd recommend going from here would be to add some sort of logging inside of the loop. Print out each "str" as soon as you get it from str = openDocument.layers.item(i).name; and see if you are seeing what you are expecting? Log the value for "LayerLength" before you run the loop, is it maybe only one item long?