Syntax comparison of Functions using CoffeeScript, Dart, and TypeScript.

functions.coffee

divisible = 3

divisibleReporter = (lastFound, nextDivisible) ->
  "Found: #{lastFound}, Next: #{nextDivisible}"

divisibleKeeper = ((divisible) ->
  lastFound = 0
  nextDivisible = divisible
  (number) ->
    if (number >= nextDivisible) 
      nextDivisible = (Math.floor(number/divisible) + 1) * divisible
      lastFound = Math.floor(number/divisible) * divisible
      console.log divisibleReporter(lastFound, nextDivisible)
  )(divisible);

for n in [1..100]
  divisibleKeeper(n)

functions.dart

int divisible = 3;

String divisibleReporter(int lastFound, int nextDivisible) => "Found: ${lastFound}, Next: ${nextDivisible}";

var divisibleKeeper = ((int divisible) {
  int lastFound = 0;
  int nextDivisible = divisible;
  return (int number){
    if (number >= nextDivisible) {
      nextDivisible = ((number/divisible).floor() + 1) * divisible;
      lastFound = (number/divisible).floor() * divisible;
      print(divisibleReporter(lastFound, nextDivisible));
    }
  };  
})(divisible);

void main() {  
  for (var i = 0; i < 100; i++) {
    divisibleKeeper(i);
  }
}

functions.ts

var divisible = 3;

var divisibleReporter = function(lastFound:number, nextDivisible:number){
  return "Found: " + lastFound + ", Next: " + nextDivisible;
};

var divisibleKeeper = (function(divisible:number) {
  var lastFound = 0;
  var nextDivisible = divisible;
  return function(number:number) {
    if (number >= nextDivisible) {
      nextDivisible = (Math.floor(number / divisible) + 1) * divisible;
      lastFound = Math.floor(number / divisible) * divisible;
      console.log(divisibleReporter(lastFound, nextDivisible));
    }
  };
})(divisible);

for (var i = 1; i <= 100; ++i) {
  divisibleKeeper(i);
}

You should consider using the Coffeescript "do" keyword for your divisibleKeeper.