CoffeeScript

CoffeeScript is a little language that compiles into JavaScript. Underneath all those awkward braces and semicolons, ang JavaScript ay palging mayroong gorgeous object model at its heart. Ang CoffeScript ay ang mas pinagandang paraan at pinadaling paraan ng JavaScript. Ikino-compile nito ang code one-to-one into the equivalent JavaScript, and there is no interpretation at runtime. Pwede mong gamitin ang anumang existing JavaScript library seamlessly from CoffeeScript.

The coffee command takes the following options:

-c, --compile             Kino-compile nito ang .coffee script into .javascipt file of the s        ame name

-i, --interactive    Launch an interactive CoffeeScript session to try short snippets. Identical to calling coffee with no arguments.

-o, --output [DIR]  Write out all compiled JavaScript files into the specified directory. Use in conjunction with --compile or --watch.

-j, --join [FILE]    Before compiling, concatenate all scripts together in the order they were passed, and write them into the specified file. Useful for building large projects.

-w, --watch                Watch files for changes, rerunning the specified command kapag ang isang file e naguupdate.

-p, --print                Instead of writing out the JavaScript as a file, pwede mo xang iprint directly sa stdout.

-l, --lint                Once na naiinstall na ang JavaSctipt Lint, maaari itong magamit para macheck ang compilation ng CoffeeScript file

-s, --stdio                Pipe in CoffeScript to STDIN and get back JavaScript over STDOUT. Good for use with the processes written in other languages. Halimbawa: cat src/cake.coffee | coffee -sc

-e, --eval                  Nagko-compile at nagpi-print ng little snippet ng CoffeeScript directly from the command line. Halimbawa: coffee –e “console.log num for num in [10..1]”

-r, --require      Nilo-load ang library before magcompile o mag-execute ng script. Can be used to hook in to the compiler.

-b, --bare         Nagko-compile ng JavaScript ng wala ang top-level function safety wrapper.

-t, --tokens              Instead of parsing the CoffeeScript, just lex it, tapos iprint out ang token stream.

-n, --nodes                Imbis na magcompile ng CoffeeScript, just lex and parse it, tapos iprint out ang parse tree.

-nodejs                        The node executable ahs some useful options you can set, such as –debug, --debug-brk and –max-stack-size. Ito ang ginagamit to forward options directly to Node.JavaScript.

First,the basics: CoffeeScript uses significant whitespace to delimit blocks of code. Hindimo na kailangang gumamit ng semicolon to terminate expressions, ending the line will do just as well (although semicolons can still be used to fit multiple expressions onto a single line). Then, instead na gumamit ng curly braces to surround blocks of code in functions, if-statement, switch, and try/catch, indentation na lang ang gamitin.

Hindi mo na kailngang gumamit ng parentheses to invoke a function if you’re passing arguments. The implicit call wraps forward to the end of the line or block expression.

Functions are defined by an optional list of parameters in parentheses, an arrow, and the function body. Tapos, ganito ang empty function: ->. It also have default  values for arguments. Override the default value by passing a non-null argument.

If, Else, Unless and Conditional AssignmentIf/else statement naman ay pdeng isulat o icode without the use of parentheses and curly braces. As with functions and other block expressions, multi-line conditionals are delimited by indentation. There’s also a handy postfix form, with the if or unless at the end.

CoffeScript can compile if statements into JavaScript expressions, gamit ang ternary operator when possible, and closure wrapping otherwise.

Most of the loops na isinususlat sa CoffeeScript will be comprehensions over array, objects and ranges. Comprehensions replace for loops, with optionalguard clauses and the value of the current array index. Unlike sa loops, ang array comprehension ay expreesion, and can be returned and assigned.

Ang natatnging low-level loop na napoprovide ng CoffeeScript ay ang while loop. Ang main difference nito sa JavaScript is that the while loop can be used as an expression, returning an array containing the result of each iteration through the loop.

Once na gagamit ka ng JavaScript loop para maggenerate ng functions, it’s common to insert a closure wrapper para maensure na ang loop variables ay closed over, then all generated functions don’t just share the final values. Nagpo-provide naman ang CoffeScript ng do keyword, which immediately invokes a passed function, forwarding any arguments.

by: Camille Abigail M. Rollan

200910643