diagram_module.js

// ref 1: http://toddmotto.com/mastering-the-module-pattern/
// ref 2: https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/fillText

// create basic diagram module (w/ "revealing module" pattern from ref 1)
var D_ = (function() {
  // draw container
  var draw = function(label) {
    var canvas = document.getElementById('canvas');
    if (canvas.getContext) {
      var ctx = canvas.getContext('2d');
      // x, y, w, h
      ctx.strokeRect(10, 10, 200, 200);
      ctx.font = "1rem sans-serif";
      // "text", x, y, max width (will squeeze text)
      ctx.fillText(label, 50, 100, 180);
    }
  };
  var step = function(label) {
    draw(label);
  };
  return {
    step: step
  };
})();

D_.step('Step 1');

// make copy of D_
// var D1_ = (function(D_){
//   var step = D_.step;
//   return {
//     step: step
//   };
// })(D_ || {});
//
// D1_.step("Step 2");