Primitives are a different kind of type than objects created from within Javascript. From the Mozilla API docs:
var color1 = new String("green");
color1 instanceof String; // returns true
var color2 = "coral";
color2 instanceof String; // returns false (color2 is not a String object)
I can’t find any way to construct primitive types with code, perhaps it’s not possible. This is probably why people use typeof "foo" === "string"
instead of instanceof
.
An easy way to remember things like this is asking yourself “I wonder what would be sane and easy to learn”? Whatever the answer is, Javascript does the other thing.