Excel JS API - SettingCollection not persisting - excel

Question

I'm trying to update my Excel add-in to use the workbook SettingCollection instead of the Office.context.document.settings object. The documentation seems to suggest they are functionally equivalent, but with document.settings I can call saveAsync() and see my data persisted (in the PropertyBag in a webextensions.xml).
With ctx.workbook.settings.add('key', 'value'), I can get the settings and get them in the current session, but they don't get added to the webextensions.xml and aren't available on the next open of the add-in.
Is there a version of saveAsync for workbook settings that I'm missing? I assumed context.sync would take care of it, but I haven't had any luck.
Edit: I figured out what was causing my initial issue, but the problem is still there. When I close the browser tab with Excel Online and re-open it with my add-in, the settings are not persisting. Nothing is getting added to webextensions.xml.
Here is an example Excel.run()
window.Excel.run(async ctx => {
ctx.workbook.settings.add('hello', 'world');
await ctx.sync();
let setting = ctx.workbook.settings.getItemOrNullObject('hello');
setting.load('value');
await ctx.sync();
console.log(setting.value);
});
The setting 'hello' sets and exists the next if I relaunch my add-in, but not if I close the file and open my add-in.

Answer 1

there is a bug with the Excel rich API for settings, can you please try the Shared API flavor as a workaround in the meantime...
function createSetting() {
Office.context.document.settings.set("Foo", "bar");
Office.context.document.settings.saveAsync();
}
function readSetting() {
console.log(Office.context.document.settings.get("Foo"));
}