In the latest Turbo PR, the team behind it decided to drop TypeScript support which to me seems like a DHH’s decision with this reasoning:

The code not only reads much better, it’s also freed of the type wrangling and gymnastics needed to please the TS compiler.

Now the code went from this:

async function gotoPageWithFormMode(page: Page, formMode: "on" | "off" | "optin") { }

to this:

async function gotoPageWithFormMode(page, formMode) { }

so this “reads better”, but what is the formMode arg, it can’t be anything.