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Comment by captn3m0 | Hacker News Reader

Ruby: x.is_a? Integer

PHP: is_int($x) (alias of is_integer)

Python: isinstance(x, int)

Node.js[1]:

    typeof val === "number" &&
    (!(typeof value !== 'number' || value !== value || value === Infinity || value === -Infinity)) && 
    Math.floor(val) === val

I think all supported Node.js versions now have Number.isInteger (via es262), but the is-integer package still gets a 200_000 downloads a week[2].

[1]: https://github.com/parshap/js-is-integer/blob/master/index.j...

[2]: https://www.npmjs.com/package/is-integer

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This actually taps into something I really like about npm. For things that "should be easy/obvious", there are usually edge cases, _especially_ around how `Object` is handled.

The real answer is for Node to have built-ins that handle this (which they now do for `isInteger`, but absent that, I love that there are these specific packages that have unit tests and a simple API. People scoff at things at `isPromise`[1], but it's reliably filling a super important niche that the language doesn't handle.

[1]: https://github.com/then/is-promise/blob/1d547300e780a4eca391...

Maybe we should adopt these packages into es262 and make the shims available by default directly with the language?

You could have found a better example. The package you referenced literally just does `Number.isInteger` unless you are on decade old versions of nodejs

It still gets downloaded and the code still runs. 200_000 times a week, irrespective of your node version.

Even when the language migrates to a standard (NumberisInteger), the remaining ecosystem keeps depending on this package.

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