cls(): 
String(undefined): undefined
String(null): null
String(42): 42
String(false): false
String("abc"): abc
String({}): [object Object]
String(undefined).split(""): u,n,d,e,f,i,n,e,d
String(null).split(""): n,u,l,l
String(42).split(""): 4,2
String(false).split(""): f,a,l,s,e
String("abc").split(""): a,b,c
String({}).split(""): [,o,b,j,e,c,t, ,O,b,j,e,c,t,]
