Type previews — the dual-view trick
A scratch page to verify one thing on a phone: a handle can hover as a compact named type, while a helper reveals its full expanded shape — the same split prettify-ts gives in the editor, reproduced here so it renders in the browser.
Both // ^? popups below are persistent (no hover needed) and sit in one block, so you see both at once — the compact name up top, the full shape right under it:
const emails: EmailsQueueconst emails: {
add: { (item: EmailJob): Effect.Effect<void>; (items: ReadonlyArray<EmailJob>): Effect.Effect<void> };
size: Effect.Effect<number>;
events: Stream.Stream<QueueEvent>;
pause: Effect.Effect<void>;
}
const shape: {
add: {
(item: EmailJob): Effect.Effect<void>
(
items: ReadonlyArray<EmailJob>
): Effect.Effect<void>
}
size: Effect.Effect<number>
events: Stream.Stream<QueueEvent>
pause: Effect.Effect<void>
}
function expand<EmailsQueue>(
x: EmailsQueue
): {
add: {
(item: EmailJob): Effect.Effect<void>
(
items: ReadonlyArray<EmailJob>
): Effect.Effect<void>
}
size: Effect.Effect<number>
events: Stream.Stream<QueueEvent>
pause: Effect.Effect<void>
}
const emails: EmailsQueueconst emails: {
add: { (item: EmailJob): Effect.Effect<void>; (items: ReadonlyArray<EmailJob>): Effect.Effect<void> };
size: Effect.Effect<number>;
events: Stream.Stream<QueueEvent>;
pause: Effect.Effect<void>;
}
const shape: {
add: {
(item: EmailJob): Effect.Effect<void>
(
items: ReadonlyArray<EmailJob>
): Effect.Effect<void>
}
size: Effect.Effect<number>
events: Stream.Stream<QueueEvent>
pause: Effect.Effect<void>
}
Top popup = the compact name EmailsQueue. Bottom popup = the same type expanded to its members. Same value, two views, on one screen.
The caveat that shaped the plan: the expansion only renders when the type arrives by inference (via expand(...)). Writing declare const x: Prettify<EmailsQueue> directly would just show Prettify — TS preserves the alias name. Thats why the real docs expand is a compiler-API port of prettify-ts (D3), not a plain type alias; and why on your machine the extension already does it for free once the handles are named.