Comments on: “Prototypal chainability”

By: Matthew

Matthew — Tue, 14 Apr 2009 20:15:28 +0000

(I suggest ‘method call chaining’. Or yeah, builder pattern.

By: Matthew

Matthew — Tue, 14 Apr 2009 20:14:50 +0000

To be clear: this doesn’t really have much to do with prototype-based OO or chaining of prototypes in javascript.

It’s just a convention that can be used in any OO language where you ‘return this’ from methods.

Probably best not to name the technique in a way that leads to confusion with javascript’s prototype-chain-based object attribute lookup semantics.

By: SaturnPolly

SaturnPolly — Tue, 14 Apr 2009 12:43:06 +0000

In the context of object creation this is also called builder pattern. Here is an example from Effective Java (2nd Edition):

NutritionFacts sodaDrink = new NutritionFacts.Builder(240, 8).calories(100).sodium(35).carbohydrate(27).build();

see http://www.javaspecialists.eu/archive/Issue163.html for more details, they talk about some of the chapters in this book.

I find it irritating to use the terms ‘prototypal’ or ‘inheritence’ though, since neither is really involved in this approach.

By: Graham B

Graham B — Mon, 13 Apr 2009 13:38:39 +0000

Chaining is a great technique if you like your scripts concise.

Just a small addition; one thing chains can’t do is give you returned data, as the returned object must always be the original instance. One way around this is to allow an optional callback parameter, so your method can return some data about the instance while invoking a new ‘chain’. Admittedly its not pretty and I don’t do it myself, but it works if you really must do everything on one line.