Maybe this is a newbie question, but I cannot find or think out the explanation.

Start the Node.js console, and:

```
> global.hasOwnProperty === hasOwnProperty
true

```

Then why

```
> global.hasOwnProperty("x")
false

```

but

```
> hasOwnProperty("x")
TypeError: Cannot convert undefined or null to object
at hasOwnProperty (<anonymous>)
at repl:1:1
at sigintHandlersWrap (vm.js:22:35)
at sigintHandlersWrap (vm.js:96:12)
at ContextifyScript.Script.runInThisContext (vm.js:21:12)
at REPLServer.defaultEval (repl.js:313:29)
at bound (domain.js:280:14)
at REPLServer.runBound [as eval] (domain.js:293:12)
at REPLServer.<anonymous> (repl.js:513:10)
at emitOne (events.js:101:20)

```

?