| x.valueOf() | |
| x.valueOf.call(undefined) | |
| TypeError: Object.prototype.valueOf: 'this' is null or undefined | |
| x.valueOf.call(null) | |
| TypeError: Object.prototype.valueOf: 'this' is null or undefined | |
| x.valueOf.call() | |
| TypeError: Object.prototype.valueOf: 'this' is null or undefined | |
| typeof x.valueOf.call(true) | |
| object | |
| typeof x.valueOf.call(42) | |
| object | |
| typeof x.valueOf.call('Hello') | |
| object |