Function nullableDecodedUndefinedEncoded

packages/effect-app/test/special.test.ts:645–664

(schema: Schema.Top)

  it("nullable to optional — from NullOr", () => {
    const nullableDecodedUndefinedEncoded = (schema: S.Top) => {
      const isNullableSchema = "members" in schema
        && globalThis.Array.isArray((schema as any).members)
        && (schema as any).members.length === 2
        && (schema as any).members.some((member: any) => member.ast._tag === "Null")

      const nullableMembers = isNullableSchema ? (schema as any).members as ReadonlyArray<S.Top> : undefined
      const innerSchema = nullableMembers
        ? nullableMembers.find((member: any) => member.ast._tag !== "Null")!
        : schema

      const nullableSchema = isNullableSchema ? schema : S.NullOr(schema)

      return nullableSchema.pipe(
        S.encodeTo(S.optionalKey(innerSchema), {
          decode: SchemaGetter.transformOptional(Option.orElseSome(() => null)),
          encode: SchemaGetter.transformOptional(Option.filter(Predicate.isNotNull))
        })
      )
    }

    const fromNullOr = nullableDecodedUndefinedEncoded(S.NullOr(S.String))
    const structFromNullOr = S.Struct({ status: fromNullOr })