I am using io-ts to build a simple record codec:

import * as t from "io-ts";

const myRecordCodec = t.record(t.string, t.string);

I think this is equivalent to the following type:

type MyRecord = Record<string, string>;

I test it as follows:

describe("myRecordCodec", () => {
  it("returns true for record", () => {
    expect(myRecordCodec.is({ a: "Oh hai, Mark!" })).toBe(true);
  });
  it("returns false for date", () => {
    const myDate = new Date();
    expect(myRecordCodec.is(myDate)).toBe(false);
  });
});

I’m surprised to find that the second test fails.

Is this expected? Am I using record correctly?