Autoboxing in JS

autoboxing-js.md

Autoboxing in JS

// calling String function like this
// will try to create a primitive value of type string from the argument which 
// is passed to the String function
String("chair") // the result is "chair"

// calling String like this
// will create new wrapper object
const chairWrapperObject = new String("chair");
// result:
// {0: "c", 1: "h", 2: "a", 3: "i", 4: "r", length: 4}

// autoboxing:
let chairString = "chair";

chairString.length = 4;
// chairString is autoboxed, which means
// that a temp wrapper object is created, then its length property is retrived
// after that the wrapper object is removed!
// the original chairString is not affected!

Autoboxing will NOT work for the folloing primitive types:

• null
• undefined