Javascript ASCII code to character and vice versa

For capital letter,

65 = A
66 = B
...
89 = Y
90 = Z

String.fromCharCode(An integer); 
e.g. 
String.fromCharCode(66) will return B
String.fromCharCode(105) will return i (lower case i )

For small letter,

a = 97
b = 98
...
z = 122

'a'.charCodeAt(0) will return 97
'cdef'.charCodeAt(3) will return 102

Javascript for/in for/of forEach and for(;;)

Javascript has different variants of iteration with different feature. Below is a summary of different for loop iteration with their features:

	For /in	For / of	Obj.forEach	Traditional for
Object Key type	All (numeric + non-numeric)	Numeric only	Numeric only	Numeric only
Index vs Value	Index only	Value only To get index Array#entries()	Index + Value  Index as the second param of callback fn	Index only
Empty element const arr = ['a',, 'c'];	Ignore empty element	Consider empty element	Ignore empty element	Consider empty element
Function Context (context of this )	this of the outer context	this of the outer context	Own version of this	this of the outer context
Async / Await + Generator	Yes	Y	With caveats and not straight forward	Y

Side topics emerged here:

Ø  ESLint

Ø  Generator

Ø  Yield

Ø  Async / Await

Source and Details: here