io-ts: utilizing TypeOf with DateFromISOString

Question

io-ts: utilizing TypeOf with DateFromISOString

struggling to validate and interpret api response:

const Bar  = t.type({
    identifier: t.number,
    timestamp: DateFromISOString,
  });

  type BarType = t.TypeOf<typeof Bar>;
  const jsonBar: BarType = {"identifier": 1, "timestamp": "2022-01-15T09:45:10.123Z"};
  const resultBar = Bar.decode(jsonBar);

the issue arises from the fact that the type defines timestamp property as a date while it's actually a string in the jsonBar

Am I overlooking something here or do I need separate types for the incoming data and decoded object?

typescript fp-ts

Answer 1

Answer №1

If you want to combine DateFromISOString and string types, you can use the 'union' function.

const Person = t.type({
      id: t.number,
      dob: t.union([DateFromISOString, t.string]),
    });

Alternatively, you can create a Date instance from a string and then convert it back to a string using the 'toISOString' helper function.

const Person = type({
      id: number,
      dob: DateFromISOString,
    });

type PersonType = TypeOf<typeof Person>;
const personData: PersonType = { id: 1, dob: new Date("2021-02-05T11:13:22.520Z") };
const resultPerson = Person.decode(personData);

const convertedDate = personData.dob.toISOString();

assert.deepStrictEqual(convertedDate, right(personData.dob)); // This assertion fails
assert.deepStrictEqual(DateFromISOString.decode(convertedDate), right(personData.dob)); // This assertion succeeds

Answer 2

If you want to combine DateFromISOString and string types, you can use the 'union' function.

const Person = t.type({
      id: t.number,
      dob: t.union([DateFromISOString, t.string]),
    });

Alternatively, you can create a Date instance from a string and then convert it back to a string using the 'toISOString' helper function.

const Person = type({
      id: number,
      dob: DateFromISOString,
    });

type PersonType = TypeOf<typeof Person>;
const personData: PersonType = { id: 1, dob: new Date("2021-02-05T11:13:22.520Z") };
const resultPerson = Person.decode(personData);

const convertedDate = personData.dob.toISOString();

assert.deepStrictEqual(convertedDate, right(personData.dob)); // This assertion fails
assert.deepStrictEqual(DateFromISOString.decode(convertedDate), right(personData.dob)); // This assertion succeeds

io-ts: utilizing TypeOf with DateFromISOString

Answer №1

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