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 pass-through 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 implementation!
• 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 credit card 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