Theo's Typesafe Cult•13mo ago

Setting Custom Error Messages on Zod Unions

Hello, I'd like to set a custom error message when a union of literals does not pass parsing in zod. With other constraints, such as .min() or .max() you can set a error message like this:

email: z
  .string()
  .email({ message: "Email must be a valid email (eg: someone@example.com).",})
  .max(255, { message: "Email must be less than 255 characters." }),

email: z
  .string()
  .email({ message: "Email must be a valid email (eg: someone@example.com).",})
  .max(255, { message: "Email must be less than 255 characters." }),

But I am not sure how to do so on this union:

gender: z.union([
  z.literal("MALE"),
  z.literal("FEMALE"),
  z.literal("NON-BINARY"),
  z.literal("OTHER"),
  z.literal("PREFERNOTSAY"),
]),

gender: z.union([
  z.literal("MALE"),
  z.literal("FEMALE"),
  z.literal("NON-BINARY"),
  z.literal("OTHER"),
  z.literal("PREFERNOTSAY"),
]),

Could anyone help me out? Thanks!

1 Reply

Alan Ibarra-2310•13mo ago

I'm not really sure how to do it. I usually just safeParse the union and if it was unsuccessful, I just write my own error message. But, if this was meant to be used in multiple places then coupling the error message with the union would be a better solution.

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Setting Custom Error Messages on Zod Unions