InDesign Books

@rebecca_7310 I have written a script that may help. (Or may not, because we don't understand your situation very well yet.)

The script performs a basic find/change operation on every section prefix in every open document. If it seems useful, give it a try.

- Mark

Screenshot 2025-11-29 at 14.22.43.png

/**
 * @file Find Change Section Prefixes.js
 *
 * Perform a find/change of section prefixes in all open documents.
 *
 * @author m1b
 * @version 2025-11-29
 * @discussion https://community.adobe.com/t5/indesign-discussions/indesign-books/m-p/15610033/thread-id/643194
 */
function main() {

    var settings = {
        findWhat: 'A',
        changeTo: 'B',
        showResults: true,
        showUI: true,
        previewFunction: getChangeCount,
    };

    if (0 === app.documents.length)
        return alert('Please open a document and try again.');

    var docs = app.documents;

    // collect all the sections
    var prefixes = [];
    var sectionPrefixes = {};

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

        for (var j = 0; j < docs[i].sections.length; j++) {

            var section = docs[i].sections[j];

            if (!sectionPrefixes[section.sectionPrefix]) {
                sectionPrefixes[section.sectionPrefix] = [];
                prefixes.push(section.sectionPrefix);
            }

            sectionPrefixes[section.sectionPrefix].push({ doc: docs[i], index: section.index });

        }

    }

    if (
        settings.showUI
        && 2 === ui(settings)
    )
        // user cancelled
        return;

    // perform the find/change
    var changeCount = findChangeSectionPrefixes();

    if (settings.showResults)
        alert('Changed ' + changeCount + ' section prefixes.');

    /** Returns the find count, without performing the change. */
    function getChangeCount() {
        // run the find/change, but preview only
        return findChangeSectionPrefixes(true);
    };

    /**
     * Performs the find/change (or just the find, if `countOnly`).
     * Note this is not a stand-alone function, it requires the
     * `prefixes` and `sectionPrefixes` objects.
     * @author m1b
     * @version 2025-11-29
     * @param {Boolean} countOnly - whether you just want the find count, without performing the change (default: false).
     * @returns {Number} - the number of instances found/changed.
     */
    function findChangeSectionPrefixes(countOnly) {

        var counter = 0;

        var method = settings.findWhat instanceof RegExp ? 'search' : 'indexOf';

        for (var i = 0, p; i < prefixes.length; i++) {

            p = prefixes[i];

            if (-1 === p[method](settings.findWhat))
                continue;

            samePrefixLoop:
            for (var j = 0; j < sectionPrefixes[p].length; j++, counter++) {

                if (countOnly)
                    continue samePrefixLoop;

                var s = sectionPrefixes[p][j];
                s.doc.sections.item(s.index).sectionPrefix = p.replace(settings.findWhat, settings.changeTo);

            }

        }

        return counter;

    };

};
app.doScript(main, ScriptLanguage.JAVASCRIPT, undefined, UndoModes.ENTIRE_SCRIPT, 'Find/Change Section Prefixes');

/**
 * UI.
 * @author m1b
 * @version 2025-11-29
 * @param {Object} settings - the settings for this script.
 * @returns {1|2} - ScriptUI result code (1 = go ahead, 2 = user cancelled).
 */
function ui(settings) {

    var previewCount = 0;

    var w = new Window("dialog", 'Find/Change Section Prefixes');
    var wrapper = w.add('Group {orientation:"column", alignment:["fill","fill"], margins:[10,10,10,10], spacing: 20 }');

    var findGroup = wrapper.add('Group {orientation:"column", alignment:["fill","top"] }');
    var findLabel = findGroup.add('StaticText {text:"Find:", preferredSize:[450,-1], alignment:["left","top"], justify:["left","top"]}');
    var findField = findGroup.add('EditText {text:"A", preferredSize:[450,-1], alignment:["left","top"], justify:["left","top"]}');

    var changeGroup = wrapper.add('Group {orientation:"column", alignment:["fill","top"] }');
    var changeLabel = changeGroup.add('StaticText {text:"Change:", preferredSize:[450,-1], alignment:["left","top"], justify:["left","top"]}');
    var changeField = changeGroup.add('EditText {text:"B", preferredSize:[450,-1], alignment:["left","top"], justify:["left","top"]}');

    var previewText = wrapper.add('StaticText {text:"", preferredSize:[450,-1], alignment:["fill","top"], justify:"right" }');

    var bottomUI = wrapper.add('Group {orientation:"row", alignment:["fill","top"], margins:[0,20,0,0] }');
    var checkboxes = bottomUI.add('Group {orientation:"column", alignment:["fill","fill"], alignChildren:["left", "top"], margins:[0,8,0,0] }');
    var useRegExpCheckbox = checkboxes.add('CheckBox { text:"Use regular expression" }');
    var buttons = bottomUI.add('Group {orientation:"row", alignment:["right","top"], alignChildren:["right","top"] }');
    var cancelButton = buttons.add('Button {text:"Cancel", properties:{ name:"cancel" } }');
    var okButton = buttons.add('Button {text:"Find/Change", properties:{ name:"ok" } }');

    // enforces a hierarchy between remove sections and combine spreads at joins
    useRegExpCheckbox.onClick = updateUI;

    findField.onChanging = function () {
        previewText.text = '';
        updateUI();
    };

    changeField.onChange = function () {
        settings.changeTo = changeField.text;
    };

    okButton.onClick = function () {
        updateUI();
        w.close(1);
    };

    updateUI();

    w.center();
    return w.show();

    function updateUI() {

        if (!findField.text)
            return;

        try {
            if (useRegExpCheckbox.value)
                settings.findWhat = new RegExp(findField.text);
            else
                settings.findWhat = findField.text;

            previewCount = settings.previewFunction();

            previewText.text = 'Will find ' + previewCount + ' instances.';

        }

        catch (error) {
            previewText.text = 'Not a valid regular expression.';
            previewCount = 0;
        }

        finally {
            okButton.enabled = previewCount > 0;
        }

    };

};

There are ways to run a script against all documents in a book. But where do the section marker and the section prefix come from? How would you know the values of the prefix and the marker for each document?