Async Data

Async Data (@ekz/async-data) models the lifecycle of asynchronous values — loading, success, failure, and stale cached data — in a type-safe container inspired by functional patterns.

It pairs well with @ekz/option for optional values and is used throughout the @ekz libraries (for example in @ekz/api).

Why use it?

• Explicit states instead of ad-hoc loading / error / data booleans
• Stale-while-revalidate via PendingStale and FailedStale
• match API for exhaustive rendering
• observePromise to wire promises into React state safely

States

State	Meaning
Empty	No value yet
Pending	Loading, no previous value
Ready	Success with a value
PendingStale	Reloading, showing previous value
Failed	Error, no previous value
FailedStale	Error after a previous value was loaded

Install

npm install @ekz/async-data @ekz/option
# or
yarn add @ekz/async-data @ekz/option

Peer dependency: @ekz/option ^2.

Next steps

• Getting started — create and transition states
• States — state machine details
• Promises — observePromise in React
• Extractors — @ekz/async-data/extractors