var clipboard = {};

clipboard.copy = (function() {
  var _intercept = false;
  var _data; // Map from data type (e.g. "text/html") to value.

  document.addEventListener("copy", function(e){
    if (_intercept) {
      for (var key in _data) {
        e.clipboardData.setData(key, _data[key]);
      }
      e.preventDefault();
    }
    _intercept = false;
  });

  return function(data) {
    return new Promise(function(resolve, reject) {
      _intercept = true; // Race condition?
      _data = (typeof data === "string" ? {"text/plain": data} : data);
      try {
        if (document.execCommand("copy")) {
          // document.execCommand is synchronous: http://www.w3.org/TR/2015/WD-clipboard-apis-20150421/#integration-with-rich-text-editing-apis
          // So we can call resolve() back here.
          resolve();
        }
        else {
          _intercept = false;
          reject(new Error("Unable to copy. Perhaps it's not available in your browser?"));
        }
      }
      catch (e) {
        _intercept = false;
        reject(e);
      }
    });
  };
}());

clipboard.paste = (function() {
  var _intercept = false;
  var _resolve;
  var _dataType;

  document.addEventListener("paste", function(e) {
    if (_intercept) {
      _intercept = false;
      e.preventDefault();
      _resolve(e.clipboardData.getData(_dataType));
    }
  });

  return function(dataType) {
    return new Promise(function(resolve, reject) {
      _intercept = true; // Race condition?
      _resolve = resolve;
      _dataType = dataType || "text/plain";
      try {
        if (!document.execCommand("paste")) {
          _intercept = false;
          reject(new Error("Unable to paste. Perhaps it's not available in your browser?"));
        }
      } catch (e) {
        _intercept = false;
        reject(new Error(e));
      }
    });
  };
}());

// Handle IE behaviour.
if (typeof ClipboardEvent === "undefined" &&
    typeof window.clipboardData !== "undefined" &&
    typeof window.clipboardData.setData !== "undefined") {

  /*! promise-polyfill 2.0.1 */
  !function(a){function b(a,b){return function(){a.apply(b,arguments)}}function c(a){if("object"!=typeof this)throw new TypeError("Promises must be constructed via new");if("function"!=typeof a)throw new TypeError("not a function");this._state=null,this._value=null,this._deferreds=[],i(a,b(e,this),b(f,this))}function d(a){var b=this;return null===this._state?void this._deferreds.push(a):void j(function(){var c=b._state?a.onFulfilled:a.onRejected;if(null===c)return void(b._state?a.resolve:a.reject)(b._value);var d;try{d=c(b._value)}catch(e){return void a.reject(e)}a.resolve(d)})}function e(a){try{if(a===this)throw new TypeError("A promise cannot be resolved with itself.");if(a&&("object"==typeof a||"function"==typeof a)){var c=a.then;if("function"==typeof c)return void i(b(c,a),b(e,this),b(f,this))}this._state=!0,this._value=a,g.call(this)}catch(d){f.call(this,d)}}function f(a){this._state=!1,this._value=a,g.call(this)}function g(){for(var a=0,b=this._deferreds.length;b>a;a++)d.call(this,this._deferreds[a]);this._deferreds=null}function h(a,b,c,d){this.onFulfilled="function"==typeof a?a:null,this.onRejected="function"==typeof b?b:null,this.resolve=c,this.reject=d}function i(a,b,c){var d=!1;try{a(function(a){d||(d=!0,b(a))},function(a){d||(d=!0,c(a))})}catch(e){if(d)return;d=!0,c(e)}}var j=c.immediateFn||"function"==typeof setImmediate&&setImmediate||function(a){setTimeout(a,1)},k=Array.isArray||function(a){return"[object Array]"===Object.prototype.toString.call(a)};c.prototype["catch"]=function(a){return this.then(null,a)},c.prototype.then=function(a,b){var e=this;return new c(function(c,f){d.call(e,new h(a,b,c,f))})},c.all=function(){var a=Array.prototype.slice.call(1===arguments.length&&k(arguments[0])?arguments[0]:arguments);return new c(function(b,c){function d(f,g){try{if(g&&("object"==typeof g||"function"==typeof g)){var h=g.then;if("function"==typeof h)return void h.call(g,function(a){d(f,a)},c)}a[f]=g,0===--e&&b(a)}catch(i){c(i)}}if(0===a.length)return b([]);for(var e=a.length,f=0;f<a.length;f++)d(f,a[f])})},c.resolve=function(a){return a&&"object"==typeof a&&a.constructor===c?a:new c(function(b){b(a)})},c.reject=function(a){return new c(function(b,c){c(a)})},c.race=function(a){return new c(function(b,c){for(var d=0,e=a.length;e>d;d++)a[d].then(b,c)})},"undefined"!=typeof module&&module.exports?module.exports=c:a.Promise||(a.Promise=c)}(this);

  clipboard.copy = function(data) {
    return new Promise(function(resolve, reject) {
      // IE supports string and URL types: https://msdn.microsoft.com/en-us/library/ms536744(v=vs.85).aspx
      // We only support the string type for now.
      if (typeof data !== "string" && !("text/plain" in data)) {
        throw new Error("You must provide a text/plain type.")
      }

      var strData = (typeof data === "string" ? data : data["text/plain"]);
      var copySucceeded = window.clipboardData.setData("Text", strData);
      copySucceeded ? resolve() : reject(new Error("Copying was rejected."));
    });
  }

  clipboard.paste = function(data) {
    return new Promise(function(resolve, reject) {
      var strData = window.clipboardData.getData("Text");
      if (strData) {
        resolve(strData);
      } else {
        // The user rejected the paste request.
        reject(new Error("Pasting was rejected."));
      }
    });
  }
}

@@ -203,24 +203,48 @@
 ntercept) %7B%0A
+    _intercept = false;%0A
       for (v
@@ -356,32 +356,8 @@
   %7D%0A
-    _intercept = false;%0A
   %7D)

Move intercept flagin copy to match paste.