How to select and display a collection

Thanks Mark, It works wonders!

I'm posting here to keep the board clean.

I have a follow up question, regarding the same script but another difficulty.

It's a question regarding event handlers and their scope.

I'm trying to navigate to a folder and select a number of files in there.

It seems there is no way around using an event handler, as the selection has to happen after the document load.

However i don't want it as a repeating behavior (not after every document load).

I was able to write a script that works, although using a logic that I haven't seen in other scripts or templates:

function listJpeg(){
    
    // Array to hold Jpeg list
    var JPGs = new Array();
    
    // for selected items, guess jpeg location and push into JPGs array
    if (app.document.selectionLength > 0){
        var thumbs = app.document.getSelection("psd,jpg,png,swf,fla,ai");
        for (var i = 0; i < thumbs.length; i++){
            var JPG = findJpeg(thumbs[i]);   // guesses the location of jpeg file and returns a thumbnail on success
            if (JPG != null) { JPGs.push( JPG ) };
        }
    }
    
    // navigate to the JPEG folder and select the files after the document has loaded
    if (JPGs.length > 0) {
        
        function onDocLoaded( event ){
            if ( event.object instanceof Document && event.type == 'loaded' ) { 
                for (var i = 0; i < JPGs.length; i++){ app.document.select (JPGs[i]) };
                app.eventHandlers.pop();
            }
            return { handled: false };
        }
    
        app.eventHandlers.push( { handler: onDocLoaded } );
        app.document.thumbnail = JPGs[0].parent;
        
    }
}

listJpeg();

Is this a safe and sound solution to my problem?

I'm not an experienced developper and I can't tell whether this is bad practice.

It seems that declaring the event handler inside the listJpeg function allows it to remember it's scope?

I'm also deleting the event handler from within it, to force it to run only once...

I also can't figure out what the "return {handled:false};" line does?

best

antoine

Hey Mark, thanks for the answer.

I'll post the next question as a new topic.

The script looks for proxy files (JPEG) that are stored in a different folder than the working files (PSD).

The logic should be simple: get selection -> find matching JPEG for each selected file -> go to JPEG folder and select corresponding files.

The part I am unsure about is how to navigate to the JPEG folder then select the corresponding files.

My first issue is how to create an event handler that has access to the scope of my function, it needs to know the array of files to select.

I solved that by declaring the handler inside my function, which seems to work. Is that a good solution?

The second issue is how to let the handler know when we need to select the files. Obviously I don't want this to happen every time I open a folder.

I solved that by un-registering the handler at the end of it's function, that makes it a single use handler? This seems dodgy as the pop method doesn't take an argument and I can't specify which handler to pop.

I also don't know whether it's good to register a new handler every time I run the script? Is it slow? will they add up in the memory?

Lastly, I'm unsure of what the line "return { handler:false }" does, it's found at the end of every event handler.

I've edited the code to help:

function select_proxys(){
     
    // get selection
    if (app.document.selectionLength > 0){ 
        var thumb_array = app.document.getSelection("psd,jpg,png,swf,fla,ai");
    } 
     
    // find corresponding proxys
    var proxy_array = find_proxys( thumb_array );


    if (proxy_array > 0) 
    { 
        // define event handler function
        function onDocLoaded( event ){ 
            if ( event.object instanceof Document && event.type == 'loaded' )
            { 
                // select the proxy thumbnails
                for (var i = 0; i < proxy_array.length; i++){
                    app.document.select (proxy_array[i]) 
                }; 
                // un-register the event handler
                app.eventHandlers.pop(); 
            } 
            return { handled: false }; 
        };
        
        // register the event handler
        app.eventHandlers.push( { handler: onDocLoaded } ); 
        // navigate to the proxy parent folder, triggering the event handler.
        app.document.thumbnail = proxy_array[0].parent; 
    };
};

select_proxys();

This script is already being launched from a contextual menu, and the paths are always relative.

I'm using an event handler because that's what recommended in the documentation in relation to the "document.select()" method.

The select method only works reliably after the document has finished loaded, so I'm listening for that event.

not sure what APITA means, apologies.

Well you're not wrong about that.