fn

This module allows to make functions with typechecking

Example:
``typescript
import { z } from 'zod'

const typedParseInt = Fn.build({
request: z.string(),
response: z.number().int()
}).init((req) => {
return parseInt(req)
})

const parsed = await typedParseInt('123')
console.log(parsed)

// Output:
// 123
`

It also supports AsyncIterators

`typescript
import { z } from 'zod'

const fn = Fn.build({
request: z.string(),
response: z.number().int(),
responseType: 'asynciterable',
}).init((req) => {
const values = req.split(' ')
return {
[Symbol.asyncIterator]: () => ({
async next () {
if (values.length === 0) {
return { done: true, value: undefined as any } // https://github.com/microsoft/TypeScript/issues/38479
}
return { value: parseInt(values.shift()!) }
},
}),
}
})

for await (const parsed of fn('123 465')) {
console.log(parsed)
}

// Output:
// 123
// 456
``

And middlewares like
lock (don't allow to call callback simultaneuosly),
cache and
expiration (allows to set timeout for callback)