isNaN expecting a number argument

[shaharkazaz]

TypeScript Version: 2.6.2

Code from lib.es6.d.ts

/**
  * Returns a Boolean value that indicates whether a value is the reserved value NaN (not a number).
  * @param number A numeric value.
  */
declare function isNaN(number: number): boolean;

Expected behavior:
The function should get any type and not only numbers.

Actual behavior:
I get an error when passing a string.

[jcalz]

Duplicate of #19153 among many, many others. Did you read the contributing guidelines as requested before you opened this issue?

[shaharkazaz]

Searched for: "is:issue is:open isNaN" but didn't see any matches, sorry for the duplicate, next time I'll search without filters 👍

[jcalz]

Yeah, I think "make sure to search closed issues also" should be made explicit in those instructions.

[RyanCavanaugh]

Didn't realize we were linking people to the terrible Issues Tab search. Sorry about that

[zpdDG4gta8XKpMCd]

the instructions to search before posting need to be in the template of the issue