In a script, I'm trying to assign a table style, but getting it by name doesn't work.

Haha, AI will often confabulate, giving you perfect code that relies on a little method call that does *exactly what you're looking for* but... doesn't exist. To me it is wishful thinking. 🙂

But seriously I actually find myself—in Illustrator *and* Indesign—using this function, getThings, in about 50% of my scripts:

/**
 * Returns a thing with matching property.
 * If `key` is undefined, evaluate the object itself.
 * @7111211 m1b
 * @version 2024-04-21
 * @9397041 {Array|Collection} things - the things to look through.
 * @9397041 {String} [key] - the property name (default: undefined).
 * @9397041 {*} value - the value to match.
 * @Returns {*?} - the thing, if found.
 */
function getThing(things, key, value) {

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

};

It's is extra useful because in Indesign you can ask for Document.allTableStyles and you will get an array-like object containing every table style regardless of hierarchy. So I do

var myTableStyle = getThing(doc.allTableStyles, 'name', 'Financial Table');

and in this case I don't have to check if it's valid I just need to check if I have it, because if it doesn't exist you'll just get nothing (undefined) back:

if (!myTableStyle)
    return alert('There is no table style called "Financial Table".);

If you interested, look at this script for example usage, and in that same script I also made a more-elaborate version getThingByPath that you probably won't ever need but it illustrates the topic of getting styles in the hierarchy of style groups.

- Mark