Apply an object style to blocks containing a certain paragraph style

Hi @99drine Here's a simple script that does what you ask. You just need to edit the name of the paragraph style and object style in the script before running.

- Mark

/**
 * @file Set Object Style Of Found Text Frames.js
 *
 * Example showing searching for a paragraph style
 * and then applying an object style to the found
 * text's frame(s).
 *
 * @author m1b
 * @version 2025-11-08
 * @discussion https://community.adobe.com/t5/indesign-discussions/apply-an-object-style-to-blocks-containing-a-certain-paragraph-style/m-p/15581289
 */
function main() {

    const TARGET_PARAGRAPH_STYLE_NAME = 'Caption Text';
    const APPLIED_OBJECT_STYLE_NAME = 'Caption Box';

    var doc = app.activeDocument;

    var targetParagraphStyle = getThing(doc.allParagraphStyles, 'name', TARGET_PARAGRAPH_STYLE_NAME);

    if (!targetParagraphStyle)
        return alert('Could not find the paragraph style "' + TARGET_PARAGRAPH_STYLE_NAME + '".');

    var appliedObjectStyle = getThing(doc.allObjectStyles, 'name', APPLIED_OBJECT_STYLE_NAME);

    if (!appliedObjectStyle)
        return alert('Could not find the object style "' + APPLIED_OBJECT_STYLE_NAME + '".');

    // find all text in target paragraph style
    app.findGrepPreferences = NothingEnum.NOTHING;
    app.findGrepPreferences.findWhat = '.*';
    app.findGrepPreferences.appliedParagraphStyle = targetParagraphStyle

    var found = doc.findGrep();

    for (var i = 0; i < found.length; i++) {
        for (var j = 0; j < found[i].parentTextFrames.length; j++) {
            found[i].parentTextFrames[j].appliedObjectStyle = appliedObjectStyle;
            found[i].parentTextFrames[j].clearObjectStyleOverrides();
        }
    }

};
app.doScript(main, ScriptLanguage.JAVASCRIPT, undefined, UndoModes.ENTIRE_SCRIPT, 'Set caption object style');

/**
 * Returns a thing with matching property.
 * If `key` is undefined, evaluate the object itself.
 * @author m1b
 * @version 2024-04-21
 * @param {Array|Collection} things - the things to look through.
 * @param {String} [key] - the property name (default: undefined).
 * @param {*} value - the value to match.
 * @returns {*?} - the thing, if found.
 */
function getThing(things, key, value) {

    for (var i = 0; i < things.length; i++)
        if ((undefined == key ? things[i] : things[i][key]) == value)
            return things[i];

};