Build fluency in Astro's type-safe server actions for forms and client calls.
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1 / 5
At standup, a dev wants a type-safe way to call server-side logic from a form without hand-rolling an API route. Which Astro feature fits?
Astro Actions let you define server-side functions with input validation that are callable from client code or HTML forms with full type safety. This avoids manually wiring a REST endpoint and parsing/validating the body yourself. It is Astro's built-in RPC-style mechanism.
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During a design review, the team wants an action's input validated against a schema before the handler runs. Which library is commonly used?
Astro Actions typically declare an input schema using Zod, and Astro validates incoming data against it before invoking the handler. Invalid input is rejected with structured errors automatically. This keeps validation declarative and colocated with the action.
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In a code review, a dev calls an action directly from an HTML form using progressive enhancement. Which attribute wires this up?
Astro Actions expose a form-compatible action value you set on a form's action attribute, so the form works even without JavaScript, then gets enhanced for client-side calls. This progressive enhancement pattern is a key design goal of Actions. It ensures accessibility and resilience without extra work.
4 / 5
An incident report shows an action's error wasn't shown to the user cleanly. Which return shape should the handler use?
Astro Actions let handlers throw an ActionError with a structured code and message, which the client can catch and render appropriately. Returning plain undefined or logging server-side loses that signal for the UI. Structured errors are the documented pattern for user-facing failures.
5 / 5
During a PR review, a teammate calls an action from client-side JavaScript rather than a form submit. Which import provides this?
Astro exposes a generated actions client object you import and call directly (e.g. actions.myAction(input)), which performs the typed request under the hood. This gives the same type safety as the form path but for programmatic calls. It unifies both usage styles behind one action definition.