Script for randomized selecting of stylistic set with each letter

Hi Finn, Here's my attempt. The script sets each selected character to a random stylistic set number, which you must specify in the script. Let me know how it goes and post a screen shot if the result looks cool!

- Mark

/**
 * Apply a random OpenType Stylistic Set to each selected character.
 * Usage: first determine which stylistic set numbers you want
 * the script to randomly choose from, eg [2,4,5] means script
 * will assign set 2 or 4 or 5 to each character. Set the value
 * of `stylisticSetNumbers` below.
 * @7111211 m1b
 * @discussion https://community.adobe.com/t5/indesign-discussions/script-for-randomized-selecting-of-stylistic-set-with-each-letter/m-p/14334161
 */
function main() {

    // you must edit these to suit your font
    var stylisticSetNumbers = [1, 2, 3];


    if (0 === app.documents.length)
        return alert('Please select some text and try again.');

    var things = app.activeDocument.selection;

    for (var i = 0, characters; i < things.length; i++) {

        if (!things[i].hasOwnProperty('characters'))
            continue;

        characters = things[i].characters.everyItem().getElements();

        for (var j = 0, r; j < characters.length; j++) {

            // random index
            r = Math.ceil(Math.random() * stylisticSetNumbers.length);

            // set the stylistic set
            setStylisticSets(characters[j], r);

        }

    }

};
app.doScript(main, ScriptLanguage.JAVASCRIPT, undefined, UndoModes.ENTIRE_SCRIPT, 'Randomize Stylistic Set');

/**
 * Set active Opentype stylistic sets.
 * @7111211 m1b
 * @version 2022-12-24
 * @9397041 {TextFrame|TextRange} text - the text.
 * @9397041 {Array<Number>} stylisticSetIndices - indices of the stylistic sets to activate.
 */
function setStylisticSets(text, stylisticSetIndices) {

    if (
        'Array' === text.constructor.name
        && text.length > 0
    )
        text = text[0];

    if (text.hasOwnProperty('textRange'))
        text = text.textRange;

    else if (text.hasOwnProperty('texts'))
        text = text.texts[0];

    if ('Array' !== stylisticSetIndices.constructor.name)
        stylisticSetIndices = [stylisticSetIndices];

    if (-1 === app.name.search(/indesign/i))
        // convert to zero-based indexing
        for (var i = 0; i < stylisticSetIndices.length; i++)
            stylisticSetIndices[i]--;

    if (text.hasOwnProperty('characterAttributes'))
        text.characterAttributes.stylisticSets = getBinaryCodedDecimalForArray(stylisticSetIndices);

    else if (text.hasOwnProperty('otfStylisticSets'))
        text.otfStylisticSets = getBinaryCodedDecimalForArray(stylisticSetIndices);

    else
        return alert('Please select some text and try again.');

};

/**
 * Returns a binary coded decimal number (BCD) representing binary bits.
 * Examples:
 * In Indesign and Illustrator, characterAttributes.stylisticSets are stored as a BCD.
 * stylistic sets 1 and 5: indices [0,4] returns 17 (10001 in binary).
 * stylistic sets 3, 4 and 5: indices [2,3,4] returns 28 (11100 in binary).
 * @9397041 {Array<Number>} numbers - the stylistic sets indices, eg. [2,4,5].
 * @Returns {Number} - the decimal number representing the numbers.
 */
function getBinaryCodedDecimalForArray(numbers) {

    var arr = numbers.slice().sort(),
        bin = [],
        len = arr[arr.length - 1],
        i = len + 1,
        val = arr.pop();

    while (i--) {
        if (val == i) {
            bin[len - i] = 1;
            val = arr.pop();
        }

        else {
            bin[len - i] = 0;
        }

    }

    // join into binary number and parse binary as decimal
    return parseInt(bin.join(''), 2);

};