@prismicio/types-internal/src/validators/NonEmptyStringOrNull.ts

Prismic types for Custom Types and Prismic Data

import { chain } from "fp-ts/Either"
import { pipe } from "fp-ts/function"
import { success, Type } from "io-ts"

import StringOrNull from "./StringOrNull"

export default new Type<string | null, string | null, unknown>(
	"nonEmptyStringOrNull",
	(u): u is string => typeof u === "string" || u === null,
	(u, c) =>
		pipe(
			StringOrNull.validate(u, c),
			chain((s) => {
				if (typeof s === "string" && s.length > 0) {
					return success(s)
				} else {
					return success(null)
				}
			}),
		),
	(s) => s,
)