Cast-unknown NPM

Cast Unknown

Cast unknown value to desired type with typescript support.

Throws CastError when value is invalid.

Current supported cast target:

string
number
object
array
date
duration (need moment package installed)
milliseconds (need moment package installed)
promise
iterable
one (one and the only one item from given iterable, otherwise undefined)
nonNull (not null or undefined)

import {
  castString,
  castNumber,
  castObject,
  castArray,
  castDate,
  castPromise,
  castIterable,
  castSoleItem,
  castNonNull,
  CastError,
} from 'cast-unknown';

castString(1);
// '1'
castNumber('2');
// 2
castObject(3);
// <throws CastError>
castArray(4);
// [4]
castArray([5]);
// [5]
castArray(null);
// []
castArray(undefined);
// []
castArray([null]);
// [null]
castArray([undefined]);
// [undefined]
castDate('2019-01-01 12:00');
// <same as `new Date('2019-01-01 12:00')`, but throws CastError if value invalid>
castPromise(6);
// async () => 6
castPromise(() => 7);
// async () => 7
castPromise(async () => 8);
// async () => 8
castIterable(9);
// [9]
const generator = (function* () {
  for (let i; i < 10; i++) {
    yield i;
  }
})();
castIterable(generator);
// generator
castIterable(null);
// []
castIterable(undefined);
// []
castOne(11);
// 11
castOne([12, 13]);
// undefined
castOne([14]);
// 14
castNonNull(15);
// 15
castNonNull(null);
// <throws CastError>
castNonNull(undefined);
// <throws CastError>