Extending z with custom types

[anthonyma94]

I'm using Day.js extensively in my application. The way to check for dayjs type is to check instanceof dayjs (the function):

import dayjs from "dayjs";
const date = dayjs();
console.log(date instanceof dayjs) // true

The param type of z.instanceof only accepts classes with constructors, but it works in runtime for checking instanceof dayjs. This means that I have to typecast dayjs as any every time I need it in instanceof:

const dateType = z.instanceof(dayjs as any);

Is there an option to extend z so that I can do something like z.dayjs()?

[anthonyma94]

So dayjs actually provides a class for me to use: z.instanceof(dayjs.Dayjs). However, I would still like to know if it's possible to extend z with custom types.

[tiavina-mika]

I'm using dayjs, too. It will be nice if we can extend z with dayjs, moment or other custom types

[plehnen]

#metoo. I am using it inside z.preprocess(v => typeof v === 'string' && v.length && dayjs(v), z.instanceof(dayjs.Dayjs)).

z.instanceof(dayjs.Dayjs) is not working. it throws "TypeError: Cannot read properties of undefined (reading 'name') at Object.instanceOfType [as instanceof]"

z.instanceof(dayjs as any) is not working. It turns the type to "any".

but z.string().min(1).transform(dayjs) (instead of preprocess) seems to work.

[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.

[stunaz]

this is a valid issue

[Yolo390]

Hi guys,

I am still wondering how to add dayjs type with zod. Any update to deal with this use case ?

Thanks

[plehnen]

I ended up using:

{
  myDayjsProp: z
    .string()
    .transform(v => (v.length && dayjs(v)) || undefined)
    .optional()
}

[Yolo390]

I ended up using:

{
  myDayjsProp: z
    .string()
    .transform(v => (v.length && dayjs(v)) || undefined)
    .optional()
}

Thanks for the workaround !

[Yolo390]

It will be nice to extend with custom types like moment or dayjs "natively".

Something like this: z.daysjs()