Scripting: Convert existing Rectangle to CheckBox

[C330 S]

tl/dr: I can’t find a way to convert existing Rectangles to CheckBox by script. 

Is this even possible?

Full story: 

I’m building a script to generate FormFields based on the text in my document. 
E.g.: Im placing an anchored Checkbox before each pair of square brackets []. 

I did already find a way, to do this in one step. This looks something like:  

var anchoredObject = doc.checkBoxes.add();
anchoredObject.anchoredObjectSettings.insertAnchoredObject(story.insertionPoints[0]);

To make it easier for the person that later on will use the script, I want to split it into two steps (seperate scripts): 

1. Place Rectangles 
2. Convert Rectangles to Checkboxes.

This way it is possible to add or remove Rectangles manually, or to make adjustments to them (CheckBoxes itself are hard to style, they behave somewhat erratic when changing e.g. their size).

One thing, I did come up with is to search these Rectangles, and then replace them with a new CheckBoxes with the same settings.

But this seems unneccesary complicated to me and I hope there is an other way to accomplish this.

[C330 S · Accepted solution]

I found the solution in these forum posts: ConvertToButton using script and How to convert textframe to button.

In case anybody else needs this, I try to document, what I put together. 

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It seems not to be possible trough the DOM. One can use a MenuAction, to invoke a menu item via script. 
This is (to my understanding) identical to selectiong the menu by hand. 

A minimal script could look like this (heavily inspired by the mentioned posts): 

#targetengine "session";

function rect_to_checkbox(rect){
    var to_checkbox = app.menuActions.item("$ID/$$$/Menu/CreateCheckBox");

    // select the rectangle
    rect.select();

    // menu item is only available, if something is selected.
    if( !to_checkbox.isValid ) return false;

    // Invoke the menu action:
    to_checkbox.invoke();
}

function main(){
    var rect  = app.documents[0].rectangles[0];
    rect_to_checkbox(rect);
}

main();

To make this work:

• you need the menu string ("$ID/...", see below)
• the item must be selected before invoking the menu item.

A big drawback is the necessity of a selection. This will slow down a script dramatically. And it looks ugly. 

--

In the post invoking menu - language it is described, how to get the locale-independent version of a menu string. 

From what I understood, the ID of a menu action is not reliable. Obviousely the same applies to localized menu strings. 

I made a small script, to get a list of all menu strings. The basic idea is from How to open any menu item … 

My script uses Peter Karels scrollable alert to show the result. 

The result is tab-delimited and can be pasted to a spreadsheet:

// Based on:
// http://kasyan.ho.ua/tips/indesign_script/all/open_menu_item.html

var myActions = app.menuActions;
var myActionsList = Array();

myActionsList.push("area\tname\tid\tkey");

for(var i = 0; i < myActions.length; i++){ 

    try{
        var key = app.findKeyStrings(String(myActions[i].title));
    } catch(e){
        key = "";
    }

    var this_line  = String(myActions[i].area) + "\t";
        this_line += String(myActions[i].name) + "\t";
        this_line += String(myActions[i].id) + "\t";
        this_line += key;

    myActionsList.push(this_line);
}

// Scrollable alert function (by Peter Kharel)
function alert_scroll (title, input){
    if (input instanceof Array) {
        input = input.join ("\r");
    }
    var w = new Window ("dialog", title);
    var list = w.add ("edittext", undefined, input, {multiline: true, scrolling: true});
    list.maximumSize.height = w.maximumSize.height-100;
    list.minimumSize.width = 800;
    w.add ("button", undefined, "Close", {name: "ok"});
    w.show ();
}

alert_scroll("MenuActions", myActionsList);

Here are the menu strings to convert an object to any interactive item: