How to use parameter as type definition?-CodePudding

Is it possible to dynamically define a parameter type based on another parameter?

Like in the following scenario:

import z from 'zod'

// I have a function that defines a command factory with a build function
const defineCommand = (name:string, schema: z.ZodTypeAny) => {
    return {
        schema,
        build: (payload: z.infer<typeof schema>) => {
            return {
                payload
            }
        }
    }
}

const CreatePostCommand = defineCommand('CreatePostCommand', z.object({
    title: z.string().min(2),
    body: z.string().min(2)
}));

// now when I call the build function there is no type check for the payload
const commandInstance = CreatePostCommand.build({foo: "bar"}) // <<-- this should cause type error

I know that it works with generics but this way I would have to pass in the "schema" twice. Once as type and once as schema object.

CodePudding user response：

With generics, there is no need to pass it twice. Check it out:

const defineCommand = <T extends z.ZodType>(name:string, schema: T) => {
    return {
        schema,
        build: (payload: z.infer<T>) => {
            return {
                payload
            }
        }
    }
}