CoffeeScript on OSX funtime
The GameTree tech stack is going to be using Jade and CoffeeScript so I ought to know how to use these things, no? Yes.
What is CoffeeScript
$ update homebrewor if you have no idea what I am talking about, install homebrew
- Then we need node.js. If you don’t have node.js, hope on in, the water is fine.
$ brew install nodeand now you follow the prompts to install our pal Node.
- Now to install CoffeeScript. `$ npm install -g coffee-script’
- Make sure it installed
$ coffee -v
You can now write
.coffee files and compile them with the
$ coffee command.
$ coffeeopens a coffeescript shell for practice
Now to learn the coffeescripting
- No more var or let or const for your variable declarations.
name = "Rusty"
- Concatenate strings with a + sign.
- String interpolation is as in HAML
- Declare function with
functionName = -> firstName + " " + lastName
- Note the lack of ending semicolon
- Note that like Ruby functions automatically return the last line of code so no
- Since there is no semi-colon you write multi-line functions with multiple lines of code. I.e. his enter/return and type like a champ.
- Create arguments for functions by putting them in parenthesis like so
name = (first_name, last_name) -> first_name + " " + last_namejust put them before the -> arrow
- Like Ruby you can omit parenthesis on arguments if you like when you call a function `name ‘Russell’, ‘Schmidt’
- Arrays are the same as ever except you can write them as multiline and omit the commas, with one entry per line. You still need square brackets.
- Similarly Objects can drop the commas when you go multi-line, and the curlies, so long as you indent, so its just
object = key: value key2: value2
- You can also use Ruby ranges like [1..10] which is inclusive of 1 and 10. Three dots [1…11] excludes the high number end and here represents the same range as [1..10]. If you just use [..] it is the size of the array.
- Splats! (
...) you can define a function with
someName...as an argument and then loop through it to take an indiscriminate number of arguments and just transform them via the function as a loop
for x in someName
- Class declarations are simple. Note whitespace being required.
class BoneMachine constructor: (fastfood) -> @fastfood = fastfood // can also be written as class BoneMachine constructor: (@fastfood) -> yourBones: @fastfood -> console.log("Your bone has a little machine") // instantiate a class myBoneMachine = BoneMachine "japanese fast food" // extend a class class BreakMyBody extends BoneMachine // overwrite inheritance yourBones -> super console.log("Im a belly dancer")
- New syntax for equivalence symbols
|true yes on||true|
|false no off||false|
The Existential Operator. Without a doubt this is my favorite thing I have ever learned in CS. ?. The question mark. You can use to check for presence
login() if not currentUser?or assign default values like the Ruby
= but here it is
?=. You can use it like a ternary operator
name = username ? 'Mr No Name'to assign a default. You can also use it like how ? is used in Swift optionals, especially in chained methods - the accessor variant of the Existential Operatol. This lets you handle null errors a little better.
- Ruby-like looping with in
sayMyName = ("Destiny's Child" for i in [0..9]to return the name 10 times in an array. It can decrement automatically too
countdown = (num for num in [10..1])
- Drop the parenthesis and curlies with conditionals.
mood = happy if singing
- While and Until keywords and loops are available with a much easier to understand syntax.
if this.studyingEconomics buy() while supply > demand sell() until supply > demand
- Switch statements are just
switch someVarand then
when x then yindented and ended with
- Switch statements can be used in place of if statements since we can pass in conditionals for each case.
when x < 100 then yinside a switch is awesome instead of relying on perfect equivalence.
- Try/Catch can omit the error variable(s) and curlies, just relying on new line and indentation.
- Block comments in CoffeeScript use
### some comments on many lines ###
Also Get your Sublime 3 Right
- Download Sublime Package control - install and restart Sublime
- In Sublime for OSX - CMD+SHFT+P
- Type “Package Control - Install Package”
- Find your package - look up “SASS” … I enjoy ‘syntax highlighting for SASS’ though