óCoffeeScript Cookbook

Wanted Recipes

Here's a list of recipes we think we need. Pick one, implement it, and remove it from the page. Alternately, add a quick note here for a recipe you'd like to see so someone else can add it.

In the notes below, "JS" means the recipe is just a simple passthrough to an existing JavaScript method.

Syntax

  • Ensuring variables are closed over # with "do"

Strings

  • HTML methods # JS .sup(), .sub(), .blink(), .link(url), etc. May not exist in your JS impl!
  • substr
str.substr(x,y)  === str[x..x+y-1] === str[x...x+y]
  • substring
str.substring(x,y) === str.slice(x,y)  === str[x..y-1] === str[x...y]
  • Replacing substrings

Arrays

  • Testing every element in an array
evens = (x for x in [0..10] by 2)
even = (x) -> x % 2 == 0
evens.every even
# => true
  • Detecting presence of matching items in an array
[1..10].some (x) -> x % 2 == 0 # => true

Math

  • square root # JS Math.sqrt
  • Constants # JS Math.PI, Math.E
  • floor, ceil, round # JS Math.floor, Math.ceil, Math.round
  • Raising a number to a power # JS Math.pow(x, y)
  • Logarithms # Math.log
  • Finding the base-n log # Math.log(num) / Math.log(base)
  • Exponents # Math.exp
  • Check if a creditcard is valid (checksum, Luhn algorithm)

Functions

  • Nested functions
hypotenuse = (a, b) ->
  square = (x) -> x * x
  Math.sqrt(square(a) + square(b))

console.log hypotenuse 3, 4
# => 5

square 5
# ReferenceError: square is not defined
  • Optional Arguments # use arg? to detect presence: if arg=0, arg? == true
foo = (a, b=42, c) -> if c? then a*b*c else a*b
[Function]
foo 6
# => 252
foo 1, 2
# => 2
foo 1, 2, 3
# => 6

Design patterns

  • Creational Patterns

    • Abstract Factory
    • Prototype
  • Structural Patterns

    • Adapter
    • Composite
    • Facade
    • Flyweight
    • Proxy
  • Behavioral Patterns

    • Chain of Responsibility
    • Iterator
    • Mediator
    • Observer
    • State
    • Template Method
    • Visitor

Databases

  • Couch access
  • MySQL/PostgreSQL access