Is function a discrete type in JavaScript?

Question

I can identify the following types in JavaScript:

number, string, boolean, object, null and undefined

But, is function a discrete type, or is it an instance of object?

Functions are instances of the Function constructor. They're objects with special runtime-supported characteristics (like, being functions). — Pointy
– Pointy, Commented Feb 17, 2015 at 22:46
Also typeof considers null to be of type Object, and undefined really isn't a type at all. — Pointy
– Pointy, Commented Feb 17, 2015 at 22:47
So the return value of typeof correspond to a superset of the types in the language? — Ben Aston
– Ben Aston, Commented Feb 17, 2015 at 22:53
Personally I think typeof is somewhat broken. A better tool to use is the .toString() function on the Object prototype: ({}).toString.call(yourValue) gives you a slightly cumbersome but less weird result than typeof. — Pointy
– Pointy, Commented Feb 17, 2015 at 22:56
Well everything that's not a scalar type - numbers, booleans, and strings - that's not null or undefined is an object (actually the values involved are references to the objects - objects are never directly "values"). — Pointy
– Pointy, Commented Feb 17, 2015 at 23:03

G Roy · Accepted Answer · 2015-02-17 22:59:25Z

1

Functions in javascript are inherited from Object. You can try the following :

var my_func = function(){};
console.log(my_func instanceof Object); // prints true
console.log(my_func instanceof Function); // also prints true

The same is true for Array.

answered Feb 17, 2015 at 22:59

G Roy

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