Upgrading from Zod 1 → Zod 2

Zod 2 is being retired and will not leave beta. This is due to some unintuitive ramifications of the transformers API: details here.

New features

• Transformers! These let you provide default values, do casting/coercion, and a lot more. Read more here: Transformers
• Asynchronous refinements and new .parseAsync and .safeParseAsync methods. Read more here: Refinements
• Modify unknown key behavior for object schemas: .strip() (the default), .passthrough(), and .strict()
• New .catchall() method for object schemas: catchall

Breaking changes

• Object schemas now strip unknown keys by default.
• Schema parsing now returns a deep clone of the data you pass in (instead of the exact value you pass in)
• Relatedly, Zod no longer supports cyclical data. Recursive schemas are still supported, but Zod can't properly parse nested objects that contain cycles.
• Optional and nullable schemas are now represented with the dedicated ZodOptional and ZodNullable classes, instead of using ZodUnion.