Falsy values are treated as `Array` type

[Szymon Marczak]

const is = require('@sindresorhus/is');

is.assert.any([is.urlInstance], undefined);

Actual:

TypeError: Expected value which is `predicate returns truthy for any value`, received value of type `Array`.

Expected:

TypeError: Expected value which is `predicate returns truthy for any value`, received value of type `undefined`.

[Sindre Sorhus]

// @scraggo

[Szymon Marczak]

The same happens with false, 0, null, NaN or even an empty string.

[Dave Cohen]

I'd like to take a look at this.

[Dave Cohen]

Started looking into it.

assert.any (source) gathers (with the spread operator) the 2nd argument, values. It then calls assertType with that gathered array as the 3rd argument.

any: (predicate: Predicate | Predicate[], ...values: unknown[]): void | never => 
// values is an array and evaluated as such in `assertType`:
assertType(is.any(predicate, ...values), AssertionTypeDescription.any, values),

So, that's why the message always fails with Array type. Given this, any failure (not just falsy values and not just predicate arrays) have the same incorrect message:

assert.any([is.string], 1);
assert.any(is.string, 1);

At the moment, I'm not sure how to address this, but I think that's the crux of the issue.

[Dave Cohen]

@sindresorhus Hi maintainers! I opened a PR to address this.