The in operator tests whether the specified property is in the specified object.
If the right operand is a of primitive type (i.e., not an object) the in operator raises a TypeError.
Noncompliant Code Example
var x = "Foo";
"length" in x; // Noncompliant: TypeError
0 in x; // Noncompliant: TypeError
Compliant Solution
var x = new String("Foo");
"length" in x; // true
0 in x; // true
"foobar" in x; // false
