ramda / ramda

For

Line 28 in 7ed79b4

var is = _curry2(function is(Ctor, val) {

improvement.

Although leet code is not a real-world scenario,
but I think is good to have an implementation to pass this exam.

The re-implementation below can pass leet code exam, maybe we can consider using this:

function is(Ctor, val) {
    if(val === null || val === undefined || typeof Ctor !== 'function') return false;
    return Object(val) instanceof Ctor;
}

another implementation is following the prototype chain

function is(Ctor, val) {
    if (val === null || val === undefined) {
      return false
    }

    if (val.constructor === Ctor){
        return true
    }

    return is(Ctor, Object.getPrototypeOf(val))
}

I don't have a strong opinion here, but a PR would be good to see along with if there are any changes in which tests pass/fail, and what new tests would pass with the change.

Both of these implementations don't work as I would expect it. Both of them would fail one of the existing examples:

is(Object, 's') // returns true, but should be false

Both of these implementations don't work as I would expect it. Both of them would fail one of the existing examples:
is(Object, 's') // returns true, but should be false

Hey @jlissner,
this is also the weird part of me, I couldn't fully understand.

In leetcode exam, they actually consider 's' is an Object instance,
but in ramda we consider 's' is not an Object instance.

I just wonder which is the standard way to understand about this.

Let's say I have a variable named maybeJson, and I know that maybeJson could either be a string or an object, like a stringified JSON or an already parsed JSON, I might write something like

const definitelyAnObject = R.when(R.is(String), JSON.parse)(maybeJson);
// or
const definitelyAnObject = R.unless(R.is(Object), JSON.parse)(maybeJson);

and I'd expect them both to work. If is(Object, 's') returns true, then my code isn't going to work as expected.

All this to say, I believe that is(Object, 's') SHOULD return false.

Let's say I have a variable named maybeJson, and I know that maybeJson could either be a string or an object, like a stringified JSON or an already parsed JSON, I might write something like
const definitelyAnObject = R.when(R.is(String), JSON.parse)(maybeJson);
// or
const definitelyAnObject = R.unless(R.is(Object), JSON.parse)(maybeJson);
and I'd expect them both to work. If is(Object, 's') returns true, then my code isn't going to work as expected.

All this to say, I believe that is(Object, 's') SHOULD return false.

Yes, the use case also make sense for me.

I think leetcode exam is not very satisfy the real world use case.
Close this issue here.

See also, https://fr.umio.us/the-philosophy-of-ramda/#somewhatsurprising for a discussion of this.

Also, I would like to point out that ECMAScript makes a distinction between a few literal values vs their object form, and 's' is a string literal, not a string object.

`is` implementation can not pass leetcode testing