canvas-lms/public/javascripts/es5_shim.js

// this just grabs Function.prototype.bind and String.prototype.trim from
// https://github.com/kriskowal/es5-shim

(function(){

  var slice = Array.prototype.slice;

  //
  // Function
  // ========
  //

  // ES-5 15.3.4.5
  // http://es5.github.com/#x15.3.4.5

  if (!Function.prototype.bind) {
      Function.prototype.bind = function bind(that) { // .length is 1
          // 1. Let Target be the this value.
          var target = this;
          // 2. If IsCallable(Target) is false, throw a TypeError exception.
          if (typeof target != "function") {
              throw new TypeError("Function.prototype.bind called on incompatible " + target);
          }
          // 3. Let A be a new (possibly empty) internal list of all of the
          //   argument values provided after thisArg (arg1, arg2 etc), in order.
          // XXX slicedArgs will stand in for "A" if used
          var args = slice.call(arguments, 1); // for normal call
          // 4. Let F be a new native ECMAScript object.
          // 11. Set the [[Prototype]] internal property of F to the standard
          //   built-in Function prototype object as specified in 15.3.3.1.
          // 12. Set the [[Call]] internal property of F as described in
          //   15.3.4.5.1.
          // 13. Set the [[Construct]] internal property of F as described in
          //   15.3.4.5.2.
          // 14. Set the [[HasInstance]] internal property of F as described in
          //   15.3.4.5.3.
          var bound = function () {

              if (this instanceof bound) {
                  // 15.3.4.5.2 [[Construct]]
                  // When the [[Construct]] internal method of a function object,
                  // F that was created using the bind function is called with a
                  // list of arguments ExtraArgs, the following steps are taken:
                  // 1. Let target be the value of F's [[TargetFunction]]
                  //   internal property.
                  // 2. If target has no [[Construct]] internal method, a
                  //   TypeError exception is thrown.
                  // 3. Let boundArgs be the value of F's [[BoundArgs]] internal
                  //   property.
                  // 4. Let args be a new list containing the same values as the
                  //   list boundArgs in the same order followed by the same
                  //   values as the list ExtraArgs in the same order.
                  // 5. Return the result of calling the [[Construct]] internal
                  //   method of target providing args as the arguments.

                  var F = function(){};
                  F.prototype = target.prototype;
                  var self = new F;

                  var result = target.apply(
                      self,
                      args.concat(slice.call(arguments))
                  );
                  if (Object(result) === result) {
                      return result;
                  }
                  return self;

              } else {
                  // 15.3.4.5.1 [[Call]]
                  // When the [[Call]] internal method of a function object, F,
                  // which was created using the bind function is called with a
                  // this value and a list of arguments ExtraArgs, the following
                  // steps are taken:
                  // 1. Let boundArgs be the value of F's [[BoundArgs]] internal
                  //   property.
                  // 2. Let boundThis be the value of F's [[BoundThis]] internal
                  //   property.
                  // 3. Let target be the value of F's [[TargetFunction]] internal
                  //   property.
                  // 4. Let args be a new list containing the same values as the
                  //   list boundArgs in the same order followed by the same
                  //   values as the list ExtraArgs in the same order.
                  // 5. Return the result of calling the [[Call]] internal method
                  //   of target providing boundThis as the this value and
                  //   providing args as the arguments.

                  // equiv: target.call(this, ...boundArgs, ...args)
                  return target.apply(
                      that,
                      args.concat(slice.call(arguments))
                  );

              }

          };
          // XXX bound.length is never writable, so don't even try
          //
          // 15. If the [[Class]] internal property of Target is "Function", then
          //     a. Let L be the length property of Target minus the length of A.
          //     b. Set the length own property of F to either 0 or L, whichever is
          //       larger.
          // 16. Else set the length own property of F to 0.
          // 17. Set the attributes of the length own property of F to the values
          //   specified in 15.3.5.1.

          // TODO
          // 18. Set the [[Extensible]] internal property of F to true.

          // TODO
          // 19. Let thrower be the [[ThrowTypeError]] function Object (13.2.3).
          // 20. Call the [[DefineOwnProperty]] internal method of F with
          //   arguments "caller", PropertyDescriptor {[[Get]]: thrower, [[Set]]:
          //   thrower, [[Enumerable]]: false, [[Configurable]]: false}, and
          //   false.
          // 21. Call the [[DefineOwnProperty]] internal method of F with
          //   arguments "arguments", PropertyDescriptor {[[Get]]: thrower,
          //   [[Set]]: thrower, [[Enumerable]]: false, [[Configurable]]: false},
          //   and false.

          // TODO
          // NOTE Function objects created using Function.prototype.bind do not
          // have a prototype property or the [[Code]], [[FormalParameters]], and
          // [[Scope]] internal properties.
          // XXX can't delete prototype in pure-js.

          // 22. Return F.
          return bound;
      };
  }


  //
  // String
  // ======
  //

  // ES5 15.5.4.20
  // http://es5.github.com/#x15.5.4.20
  var ws = "\x09\x0A\x0B\x0C\x0D\x20\xA0\u1680\u180E\u2000\u2001\u2002\u2003" +
      "\u2004\u2005\u2006\u2007\u2008\u2009\u200A\u202F\u205F\u3000\u2028" +
      "\u2029\uFEFF";
  if (!String.prototype.trim || ws.trim()) {
      // http://blog.stevenlevithan.com/archives/faster-trim-javascript
      // http://perfectionkills.com/whitespace-deviations/
      ws = "[" + ws + "]";
      var trimBeginRegexp = new RegExp("^" + ws + ws + "*"),
          trimEndRegexp = new RegExp(ws + ws + "*$");
      String.prototype.trim = function trim() {
          if (this === undefined || this === null) {
              throw new TypeError("can't convert "+this+" to object");
          }
          return String(this).replace(trimBeginRegexp, "").replace(trimEndRegexp, "");
      };
  }
})();