A static method belongs to a constructor function or class, so callers access it through that constructor rather than through an object instance. Use it for operations that work with supplied objects but do not require one particular instance. section 4.2.6 section 4.2.7
JavaScript constructor function
A function is an object, so JavaScript permits a method to be assigned directly to it. Product.process accepts several products and invokes each product's instance toString method. Call it as Product.process(...), not product.process(...). section 4.2.6
Class syntax expresses the same distinction with the static keyword. TaxedProduct.process is called through the class, while toString and getPriceIncTax are called on each TaxedProduct object. A static method can still process instance methods on objects it receives. section 4.2.7
Keep these access rules in mind:
- Call a static method through its constructor or class, such as TaxedProduct.process(...). section 4.2.7
- Do not expect a static method to appear on instances; instance methods and static methods occupy different access paths. section 4.2.6
- Give a static method its own generic type parameters when it must operate on varying typed data. section 12.3.8
Static methods on generic classes
DataCollection<T> has instance members associated with T, but its static reverse method is accessed as DataCollection.reverse(cities). Declaring reverse<ArrayType> gives the method its own type parameter, independent of the class's T. section 12.3.8
