debounce.js

/*
  Wraps `f` such that the resulting function can be invoked at most once per `milliseconds`.
  The first invocation has the same effect and return value as `f`. Subsequent invocations
  within the buffer timeframe have the same return value as `f` but do not side effect.
  Note that `f` should not be recursive. If `f` recurses, the return value of this function
  will be `undefined`.
*/

function debounce(f, milliseconds) {

  milliseconds = milliseconds || 1000;

  var buffer;

  return function () {

    if (!buffer) {

      buffer = {};

      buffer.value = f.apply(this, arguments);

      buffer.timeout = setTimeout(
        function () { 
          buffer = undefined;
        },
        milliseconds
      );
    }

    return buffer.value;
  };
}