CoffeeScript lazy singleton class instance function

Explanation

“@instance:” allows us to attach an object/value to the Foo class instead of Foo’s prototype. Recall that “@” in CoffeeScript refers to JavaScript’s “this”.

After “@instance:” there is a function that is immediately executed. This function returns a function, closed around a variable called instance. Both these functions have their context (their “this”) bound to the Foo object using CoffeeScript’s wonderful “define and bind” operator “=>” as opposed to the normal function definition operator “->”.

When called, the function that “@instance” ends up referring to simply checks to see if the “instance” variable is empty and if so, assigns a new instance of Foo to it. Newing up a Foo is done using the “@” symbol since the function’s “this” refers to the Foo object. It then returns the instance.

Output

The CoffeeScript above compiles down to this:

17,466 thoughts on “CoffeeScript lazy singleton class instance function

  1. ORBS Production https://filmproductioncortina.com is a full-service film photo and video production company in Cortina d’Ampezzo and the Dolomites. We create commercials branded content sports and winter campaigns with local crew alpine logistics aerial/FPV filming and end-to-end production support across the Alps. Learn more at filmproductioncortina.com

  2. Flat Roofing is crucial as homeowners must prioritize safety first always embracing solutions before issues arise unexpectedly keeping tabs regularly thus preventing costly repairs further down road altogether quite beneficial indeed seen firsth Free Roofing Quote Surrey

  3. I’m extremely impressed together with your writing
    talents as well as with the format to your blog.
    Is that this a paid theme or did you modify it yourself?
    Anyway keep up the nice high quality writing, it is uncommon to
    look a nice blog like this one these days..

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>