Handle NaN as input value

[IvanGoncharov]

No description provided.

[IvanGoncharov]

== null block null and undefined but not a NaN and simular values

graphql-js/src/jsutils/isNullish.js

Lines 13 to 15 in 85971a2

	export default function isNullish(value: mixed): boolean %checks {
	return value === null || value === undefined || value !== value;
	}

[IvanGoncharov]

Safe because it only used here:

graphql-js/src/utilities/coerceValue.js

Lines 61 to 71 in 85971a2

	if (isNullish(value)) {
	// Explicitly return the value null.
	return ofValue(null);
	}
	if (isScalarType(type)) {
	// Scalars determine if a value is valid via parseValue(), which can
	// throw to indicate failure. If it throws, maintain a reference to
	// the original error.
	try {
	const parseResult = type.parseValue(value);

So null and undefined values are never passed to parseValue.
Even though it's not breaking anything in graphql-js it's still a minor breaking change since there is a chance that someone using parseValue directly.

[mjmahone]

I think this makes sense to include in 14.0: as you said, removing the isInvalid => undefined case is a slight breaking change.