import is, { type AssertionType } from 'sarcastic';

const PKG_SHAPE = is.shape({
  name: is.string,
  version: is.string,
  private: is.maybe(is.boolean),
  scripts: is.maybe(is.objectOf(is.string)),
  bin: is.maybe(is.either(is.string, is.arrayOf(is.string))),
});

type PkgShape = AssertionType<typeof PKG_SHAPE>;

function assertPkg(pkg: mixed): PkgShape {
  return is(pkg, pkgShape, 'pkg');
}

let pkg = assertPkg(require('./package.json'));
// type:
//   {
//     name: string,
//     version: string,
//     private: boolean | null,
//     scripts: { [key: string]: string } | null,
//     bin: string | Array<string> | null
//   }

is(true, is.boolean);
is(true, is.boolean, "example");

is(true, is.boolean); // returns true
is(false, is.boolean); // returns false
is(42, is.boolean); // throws instanceof is.AssertionError

is(42, is.number); // returns 42
is(NaN, is.number); // returns NaN
is(true, is.number); // throws instanceof is.AssertionError

is("", is.string), ""); // returns ""
is("hi", is.string); // returns "hi"
is(true, is.string); // throws instanceof is.AssertionError

is([], is.array); // returns []
is([1, 2, 3], is.array); // returns [1, 2, 3]
is({}, is.array); // throws instanceof is.AssertionError

is({}, is.object); // returns {}
is({ foo: true }, is.object); // returns { foo: true }
is([], is.object); // throws instanceof is.AssertionError
is(null, is.object); // throws instanceof is.AssertionError

is([], is.arrayOf(is.number)); // returns []
is([1, 2, 3], is.arrayOf(is.number)); // returns [1, 2, 3]
is({}, is.arrayOf(is.number)); // throws instanceof is.AssertionError
is(["hi"], is.arrayOf(is.number)); // throws instanceof is.AssertionError

is(1, is.arrayish(is.number)); // returns [1]
is([], is.arrayish(is.number)); // returns []
is([1, 2, 3], is.arrayish(is.number)); // returns [1, 2, 3]
is("hi", is.arrayish(is.number)); // throws instanceof is.AssertionError
is({}, is.arrayish(is.number)); // throws instanceof is.AssertionError
is(["hi"], is.arrayish(is.number)); // throws instanceof is.AssertionError

is({}, is.objectOf(is.boolean)); // returns {}
is({ foo: true }, is.objectOf(is.boolean)); // returns { foo: true }
is([], is.objectOf(is.boolean)); // throws instanceof is.AssertionError
is(null, is.objectOf(is.boolean)); // throws instanceof is.AssertionError
is({ foo: 42 }, is.objectOf(is.boolean)); // throws instanceof is.AssertionError

let myShape = is.shape({ foo: is.boolean });

is({ foo: true }, myShape); // returns { foo: true
is({ foo: true, bar: false }, myShape); // returns { foo: true }
is([], myShape); // throws instanceof is.AssertionError
is(null, myShape); // throws instanceof is.AssertionError
is({ foo: 42 }, myShape); // throws instanceof is.AssertionError

is(undefined, is.maybe(is.boolean)); // returns null
is(null, is.maybe(is.boolean)); // returns null
is(true, is.maybe(is.boolean)); // returns true
is(42, is.maybe(is.boolean)); // throws instanceof is.AssertionError

is(undefined, is.default(is.number, 42)); // returns 42
is(null, is.default(is.number, 42)); // returns 42
is(3.14, is.default(is.number, 42)); // returns 3.14
is("hi", is.default(is.number, 42)); // throws instanceof is.AssertionError

is(true, is.either(is.boolean, is.string)); // returns true
is("hi", is.either(is.boolean, is.string)); // returns "hi"
is(42, is.either(is.boolean, is.string)); // throws instanceof is.AssertionError

try {
  is(true, is.number);
} catch (err) {
  if (err instanceof is.AssertionError) {
    // an assertion error
  } else {
    // some other unexpected error
  }
}