Here is my CoffeeScript:
buffer = new Buffer 100 buffer[i] = i for i in [0..99] console.log buffer
which compiles to
var
Ray nailed it in his comment. See the Buffer documentation; you have to specify an encoding argument (you probably want 'utf8') on a Buffer's toString.
encoding
'utf8'
toString
// coffeescript console.log buffer.toString 'utf8' // javascript console.log(buffer.toString('utf8'));