is-unlucky

An npm package to check if a number is unlucky. Meant as an alternative to is-thirteen.

Why use it?

1. You might want to use is-thirteen to find whether a number is unlucky. However, that may cause trouble for people in other parts of the world where different numbers are unlucky. For example, in Japan, 4 and 9 are considered unlucky. This package considers 4, 9, 13, and 17 to be unlucky, and issues with more unlucky numbers from other cultures are welcome.

2. This package also can be used to test whether numbers are lucky. 7 and 8 are considered lucky.

3. If you really wanted to check whether a number is 13, you still can. Just use the thirteen method!

4. The syntax is pleasantly English-like, as seen in the examples below this list.

5. There is 100% test coverage.

6. is-unlucky exposes all its internals in an internals export, so if you want to play around with it you can.

7. is-unlucky is more honest than is-thirteen about whether something is 13. Let's face it: the letter B is not thirteen, neither is it unlucky.

8. It has testing for whether a number is 8, not just 13. This can be extended to other numbers by users via the define function.

Examples

const {is, are, does} = require('./');

is(13).unlucky(); // true
is(4).unlucky(); // true

is(4).plus(5).unlucky();      // true
is(12).plus(1).unlucky();    // true
is(4).minus(12).unlucky();    // false
is(14).minus(1).thirteen();    // true
is(1).times(8).unlucky();    // false
is(26).dividedBy(2).unlucky();  // true

is(8).lucky(); // true
is(3).plus(4).lucky(); // true
is(8).not.unlucky(); // true

is(8).thirteen(); // false
is(8).plus(5).thirteen(); // true
is(8).eight(); // true

does([1, 2, 13]).contain.any.unluckyNumbers(); // true
does([1, 2, 13]).contain.only.unluckyNumbers(); // false
does([1, 2, 13]).contain.any.eight(); // false
are.any.of([1, 2, 3]).lucky(); // false

is('B').thirteen(); // false
is('B').unlucky(); // false

License

MIT