2. functional js: hiding state in a closure via https://youtu.be/kA4-b7hvWhg

after.js

// run: https://repl.it/EU15/3

function writeComment(count, author, text) {
 if(count > 3) {
   throw new Error(author + 'executed too many actions!!');
 }
  console.log(author, text); // saveComment(author, text);
  return count + 1; 
}

// add a function with two closures
// one risk, can't easily cache, i don't know what that means... yet
function makeWriteCommentFunction(author) {
  var counter = 0;
  return function(text) {
    counter = writeComment(counter, author, text);
  }
}

var currentUserWritesComment = makeWriteCommentFunction('byron');
currentUserWritesComment('Check out my stuff');
currentUserWritesComment('Check out my stuff');
currentUserWritesComment('Check out my stuff');
currentUserWritesComment('Check out my stuff');
currentUserWritesComment('Check out my stuff');

before.js

function writeComment(count, author, text) {
 if(count > 3) {
   throw new Error(author + 'executed too many actions!!');
 }
  console.log(author, text); // saveComment(author, text);
  return count + 1; 
}

var counter = 0;
counter = writeComment(counter, 'bbuckley', 'Check this out');
counter = writeComment(counter, 'bbuckley', 'Check this out');
counter = writeComment(counter, 'bbuckley', 'Check this out');
counter = writeComment(counter, 'bbuckley', 'Check this out');
counter = writeComment(counter, 'bbuckley', 'Check this out');