Provide a clear way to work with dates

[cyrilchapon]

Working with dates is inherently a little complex when typing an API.

There are currently 2 use-cases that I would like to see covered in such a library like Zodios :

• datetime validation / parsing of params
• datetime validation / parsing in response body DTOs

---

What I naïvely tried first :

api-def.ts

import { makeEndpoint, makeApi } from '@zodios/core'
import { z } from 'zod'

const stuffDTO = z.object({
  someName: z.string(),
  someDate: z.date(),
})

export const getStuffByDate = makeEndpoint({
  method: 'get',
  path: '/stuff/:stuff/word',
  response: stuffDTO,
  alias: 'getStuffByDate',
  description: 'Get a stuff by date',
  parameters: [
    {
      type: 'Path',
      name: 'date',
      schema: z.date(),
    },
  ],
})

export const apiDefinition = makeApi([getStuffByDate])

handler.ts

import { ApiDefinition } from './api-def'
import { ZodiosRequestHandler } from '@zodios/express'

import { ContextShape } from '../context'

export const getDayword: ZodiosRequestHandler<
  ApiDefinition,
  ContextShape,
  'get',
  '/date/:date/stuff'
> = async (req, res) => {
  const { date } = req.params

  res.json({
    someName: 'A stuff',
    someDate: date,
  })
}

component.tsx

import { StatusBar } from 'expo-status-bar'
import { Skeleton } from 'moti/skeleton'
import { FunctionComponent, useMemo } from 'react'
import { StyleSheet, View, ViewProps } from 'react-native'
import { Divider, Text } from 'react-native-paper'

import { apiHooks } from '../api'
import { AppTheme, useAppTheme } from '../style/theme'

const now = new Date(Date.now())

export const MainView: FunctionComponent<ViewProps> = (props) => {
  const theme = useAppTheme()
  const styles = useMemo(() => getStyles(theme), [theme])

  const result = apiHooks.useGetWordByLanguageAndDate(
    { params: { date: now } },
  )

  return (
    <View style={styles.container}>
      <Text>Hello</Text>
    </View>
  )
}

I was naively thinking that both

in server

  const app = ctx.app(apiDefinition, {
    express: _app,
    validate: true,
    transform: true, // Activate transformation
  })

and in client

export const apiClient = new Zodios(appEnv.EXPO_PUBLIC_API_URL, apiDefinition, {
  validate: true,
  transform: true,
})

would do the trick, but apparently not.

---

So I thought "hey, actually I have to tell Zodios how to serialize and parse the date". And gave a shot :

const coercedDateSchema = z
  .string()
  .datetime( { offset: true } )
  .pipe( z.coerce.date() )

const stuffDTO = z.object({
  someName: z.string(),
  someDate: coercedDateSchema,
})

But the trick is now (with transforms) both the server-side and the client side expects a string So I went :

in server

  res.json({
    someName: 'A stuff',
    someDate: date.toISOString(), // convert to string
  })

and in client

  const result = apiHooks.useGetWordByLanguageAndDate(
    { params: { date: now.toISOString() } }, // convert to string
  )

But I had to disable transformation for request in the client

export const apiClient = new Zodios(appEnv.EXPO_PUBLIC_API_URL, apiDefinition, {
  validate: true,
  transform: 'response', // Response only, on reception
})

This is now sort of "working", but I don't find it elegant.

I extensively searched "Zodios date" accross repos issues and discussions without any success; and I'm pretty surprised I'm the first to encounter this. Am I missing something ?

---

As a side note; the recommended way to parse dates string in zod is the following.

const coercedDateSchema = z
  .string()
  .datetime( { offset: true } )
  .pipe( z.coerce.date() )

Which accepts a string in input, validate its appearance as an ISO8601 datetime, then coerces it into a Date object. Perfect.

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[rottmann]

Had the same problem and found a "simpler" solution https://github.com/colinhacks/zod/discussions/879#discussioncomment-7292834 :

const stringToValidDate = z.coerce.date().transform((dateString, ctx) => {
  const date = new Date(dateString)
  if (!z.date().safeParse(date).success) {
    ctx.addIssue({
      code: z.ZodIssueCode.invalid_date,
    })
  }
  return date
})

const stuffDTO = z.object({
  someName: z.string(),
  someDate: stringToValidDate, // it is a Date 
})