gem-hunterNote
This package is mostly unmaintained, if you're a fan of Go, codegen and Zod then check out Schemancer:
https://github.com/Southclaws/schemancer
Schemancer takes a different approach where your shared data structures' source of truth is not code, but JSON Schemas, from which you can generate Go structs and TypeScript Zod schemas.
Plus, Schemancer also supports discriminated unions which this package does not, as well as other features not as easy to express via Go structs alone.
Converts Go structs to Zod schemas.
Usage:
type Post struct { Title string } type User struct { Name string Nickname *string // pointers become optional Age int Height float64 Tags []string Favourites []struct { // nested structs are kept inline Name string } Posts []Post // external structs are emitted as separate exports } StructToZodSchema(User{})
Outputs:
export const PostSchema = z.object({ title: z.string(), }); export type Post = z.infer<typeof PostSchema>; export const UserSchema = z.object({ name: z.string(), nickname: z.string().optional(), age: z.number(), height: z.number(), tags: z.string().array(), favourites: z .object({ name: z.string(), }) .array(), posts: PostSchema.array(), }); export type User = z.infer<typeof UserSchema>;
If a field is declared with a JSON tag prefixed with -, and subsequently also
present inside an inlined struct, the embedded field will be omitted.
package main import ( "fmt" ) type BaseType struct { ID string `json:"id"` Name string `json:"name"` Start int `json:"start"` End int `json:"end"` } type FinalType struct { Start int `json:"-start"` End int `json:"-end"` BaseType `json:",inline"` } func main() { fmt.Println(StructToZodSchema(FinalType{})) // export const FinalTypeSchema = z.object({ // id: z.string(), // name: z.string(), // }) // export type FinalType = z.infer<typeof FinalTypeSchema> }
You can define a custom conversion using a ZodSchema() method. This should have one of the following types:
ZodSchema() string ZodSchema(c *supervillain.Converter, t reflect.Type, name, generic string, indent int) string ZodSchema(convert func(t reflect.Type, name string, indent int) string, t reflect.Type, name, generic string, indent int) string
(The first signature is available to simplify the simple case; the last signature is available in case you do not want the package defining the type to depend on supervillain.)
Zod will obtain a schema by creating a zero value of your type and calling its ZodSchema() method.
type State int func (s State) MarshalJSON() ([]byte, error) { return json.Marshal(fmt.Sprint(s)) } func (s State) ZodSchema() string { return "z.string()" } type Job struct { State State } c.Convert(Job{})
Outputs:
export const JobSchema = z.object({ State: z.string(), }) export type Job = z.infer<typeof JobSchema>
If you don't control the type yourself, you can also pass a map of type names to custom conversion functions:
c := supervillain.NewConverter(map[string]supervillain.CustomFn{ "github.com/shopspring/decimal.Decimal": func(c *supervillain.Converter, t reflect.Type, s, g string, i int) string { // Shopspring's decimal type serialises to a string. return "z.string()" }, }) c.Convert(User{ Money decimal.Decimal })
Outputs:
export const UserSchema = z.object({ Money: z.string(), }) export type User = z.infer<typeof UserSchema>
There are some custom types with tests in the "custom" directory.
The function signature for custom type handlers is:
func(c *supervillain.Converter, t reflect.Type, typeName, genericTypeName string, indentLevel int) string
You can use the Converter to process nested types. The genericTypeName is the name of the T in Generic[T] and the indent level is for passing to other converter APIs.
Types with a custom MarshalJSON() method but no custom schema are typically problematic, since the generated schema may not match the custom marshalled format. You can use the WithStrictCustomSchemas option to cause conversion to fail (panic) if such a type is found:
c := NewConverter(map[string]CustomFn{}, WithStrictCustomSchemas(true)) // or StructToZodSchema(User{}, WithStrictCustomSchemas(true))
