method-cache

I micro library that provides a simple method cache that works well with CoffeeScript class methods and can be used in an annotation style or as a mixin.

All memoized method definitions are a variation on a basic signature:

# cacheName - (mandatory) name of the field on the context object to use as the cache
# func - (mandatory) method implementation
# resolver - optional cache key derivation function 
(cacheName, func, resolver) ->

The basic, verbose, usage is:

cache = require('method-cache').cacheMethod

TestClass = class
  doit1: cache '__doit1', (arg1, arg2) -> "#{arg1},#{arg2}"

  doit2: cache '__doit2', (arg1, arg2) ->
    "#{arg1},#{arg2}"
  , (arg1, arg2) -> arg2

Alternatively methods can be defined in an "annotation" style:

cache = require('method-cache').annotate

TestClass = class
  doit1: cache('__doit1') (arg1, arg2) -> "#{arg1},#{arg2}"

  doit2: cache('__doit2') (arg1, arg2) ->
    "#{arg1},#{arg2}"
  , (arg1, arg2) -> arg2

  # specifying resolver in annotation

  doit3: cache('__doit3', (arg1, arg2) -> arg2) (arg1, arg2) ->
    "#{arg1},#{arg2}"

Methods can be defined directly on the prototype via the shorthand:

define = (proto, name) ->

Example:

cache = require('../index').define

TestClass = class
  cache(@::, 'doit1') (arg1, arg2) -> "#{arg1},#{arg2}"

  cache(@::, 'doit2') (arg1, arg2) ->
    "#{arg1},#{arg2}"
  , (arg1, arg2) -> arg2

To specify the resolver function first, use defineWithResolver:

cache = require('../index').defineWithResolver

TestClass = class
  cache(@::, 'doit1') (arg1, arg2) -> "#{arg1},#{arg2}"

  cache(@::, 'doit2', (arg1, arg2) -> arg2) (arg1, arg2) ->
    "#{arg1},#{arg2}"

Finally, specifying the prototype can be avoided by using a mixin:

cachable = require('method-cache').cachable

TestClass = class
  _.extend @, cachable

  @cacheMethod('doit1') (arg1, arg2) -> "#{arg1},#{arg2}"

  @cacheMethod('doit2') (arg1, arg2) ->
    "#{arg1},#{arg2}"
  , (arg1, arg2) -> arg2

  # specifying resolver in definition function

  @cacheMethod('doit3', (arg1, arg2) -> arg2) (arg1, arg2) ->
    "#{arg1},#{arg2}"