Question

Could someone please explain the following?

[] instanceof Array; // true
'' instanceof String; // false

Answer 1

Note the following:

"" instanceof String;             // => false
new String("") instanceof String; // => true

instanceof requires an object, but "" is a string literal, and not a String object. Note the following types using the typeof function:

typeof ""             // => "string"
typeof new String("") // => "object"
typeof []             // => "object"
typeof new Array()    // => "object"