ian•13mo ago

Want branded strings or more specific

Want branded strings or more specific types? I just realized this just works:

defineSchema({
  myTable: defineTable({
    myField: v.string() as Validator<MyStringType>
  })
)}

defineSchema({
  myTable: defineTable({
    myField: v.string() as Validator<MyStringType>
  })
)}

myField will be typed as MyStringType when you get it from the DB, and give you errors on functions like withIndex if your parameter isn't MyStringType when comparing against myField Note: this isn't runtime validation, this is just type annotations to help you catch bugs & be more descriptive.

3 Replies

wjarjoui•13mo ago

This looks super cool! Can you elaborate on what MyStringType could look like?

ianOP•13mo ago

export type MyStringType = string & { __myStringType: never }; Better yet, here's a little article on it I just wrote for you: https://stack.convex.dev/using-branded-types-in-validators

Using branded types in validators

If you have a more specific type than what you can express with Convex validators, you can still document that at the type level in Convex by casting ...

ianOP•13mo ago

Can chat about it here: https://discord.com/channels/1019350475847499849/1198117197638291546

Want branded strings or more specific

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