Enforce script execution order in `browser.coffee`.

lib/browser.js

@@ -1,5 +1,6 @@
 (function() {
-  var CoffeeScript, runScripts;
+  var CoffeeScript, create, document, runScripts;
+  var __bind = function(fn, me){ return function(){ return fn.apply(me, arguments); }; };
   CoffeeScript = require('./coffee-script');
   CoffeeScript.require = require;
   CoffeeScript.eval = function(code, options) {
@@ -12,41 +13,67 @@
     options.bare = true;
     return Function(CoffeeScript.compile(code, options))();
   };
-  if (typeof window == "undefined" || window == null) {
-    return;
+  document = typeof this.document !== 'undefined' ? document : null;
+  create = function() {
+    throw new Error('`XMLHttpRequest` is not supported.');
+  };
+  if (typeof this.ActiveXObject !== 'undefined') {
+    create = __bind(function() {
+      return new this.ActiveXObject('Microsoft.XMLHTTP');
+    }, this);
+  } else if (typeof this.XMLHttpRequest !== 'undefined') {
+    create = __bind(function() {
+      return new this.XMLHttpRequest;
+    }, this);
   }
-  CoffeeScript.load = function(url, options) {
+  CoffeeScript.load = function(url, options, callback) {
     var xhr;
-    xhr = new (window.ActiveXObject || XMLHttpRequest)('Microsoft.XMLHTTP');
+    xhr = create();
     xhr.open('GET', url, true);
     if ('overrideMimeType' in xhr) {
       xhr.overrideMimeType('text/plain');
     }
     xhr.onreadystatechange = function() {
+      var error, result;
       if (xhr.readyState === 4) {
-        return CoffeeScript.run(xhr.responseText, options);
+        error = result = null;
+        if (xhr.status === 200) {
+          try {
+            result = CoffeeScript.run(xhr.responseText);
+          } catch (error) {
+            error = exception;
+          }
+        } else {
+          error = new Error("An error occurred while loading the script `" + url + "`.");
+        }
+        return typeof callback == "function" ? callback(error, result) : void 0;
       }
     };
     return xhr.send(null);
   };
   runScripts = function() {
-    var script, _i, _len, _ref;
-    _ref = document.getElementsByTagName('script');
-    for (_i = 0, _len = _ref.length; _i < _len; _i++) {
-      script = _ref[_i];
-      if (script.type === 'text/coffeescript') {
-        if (script.src) {
-          CoffeeScript.load(script.src);
-        } else {
-          CoffeeScript.run(script.innerHTML);
-        }
+    var execute, index, length, scripts;
+    scripts = document.getElementsByTagName('script');
+    index = 0;
+    length = scripts.length;
+    (execute = function(error) {
+      var script;
+      if (error) {
+        throw error;
       }
-    }
+      script = scripts[index++];
+      if (script.type === 'text/coffeescript' && script.src) {
+        return CoffeeScript.load(script.src, null, execute);
+      } else {
+        CoffeeScript.run(script.innerHTML);
+        return execute();
+      }
+    })();
     return null;
   };
-  if (window.addEventListener) {
-    addEventListener('DOMContentLoaded', runScripts, false);
-  } else {
-    attachEvent('onload', runScripts);
+  if (typeof this.addEventListener !== 'undefined') {
+    this.addEventListener('DOMContentLoaded', runScripts, false);
+  } else if (typeof this.attachEvent !== 'undefined') {
+    this.attachEvent('onload', runScripts);
   }
 }).call(this);

src/browser.coffee

@@ -12,32 +12,55 @@ CoffeeScript.run = (code, options = {}) ->
   options.bare = on
   Function(CoffeeScript.compile code, options)()
 
-# If we're not in a browser environment, we're finished with the public API.
-return unless window?
+# Capture a reference to the `document` object in the browser.
+document = if typeof @document isnt 'undefined' then document else null
 
-# Load a remote script from the current domain via XHR.
-CoffeeScript.load = (url, options) ->
-  xhr = new (window.ActiveXObject or XMLHttpRequest)('Microsoft.XMLHTTP')
-  xhr.open 'GET', url, true
+# Creates a new `XMLHttpRequest` object in IE and W3C-compliant browsers.
+create = -> throw new Error '`XMLHttpRequest` is not supported.'
+if typeof @ActiveXObject isnt 'undefined'
+  create = => new @ActiveXObject 'Microsoft.XMLHTTP'
+else if typeof @XMLHttpRequest isnt 'undefined'
+  create = => new @XMLHttpRequest
+
+# Load a remote script from the current domain via XHR. The optional `callback`
+# function accepts two arguments: an error object if the script could not be
+# loaded or failed to run, and the result of executing the script using
+# `CoffeeScript.run`.
+CoffeeScript.load = (url, options, callback) ->
+  xhr = create()
+  xhr.open 'GET', url, yes
   xhr.overrideMimeType 'text/plain' if 'overrideMimeType' of xhr
   xhr.onreadystatechange = ->
-    CoffeeScript.run xhr.responseText, options if xhr.readyState is 4
+    if xhr.readyState is 4
+      error = result = null
+      if xhr.status is 200
+        try result = CoffeeScript.run xhr.responseText catch error then error = exception
+      else
+        error = new Error "An error occurred while loading the script `#{url}`."
+      callback? error, result
   xhr.send null
 
-# Activate CoffeeScript in the browser by having it compile and evaluate
-# all script tags with a content-type of `text/coffeescript`.
-# This happens on page load.
+# In the browser, the CoffeeScript compiler will asynchronously load, compile,
+# and evaluate all `script` elements with a content type of 
+# `text/coffeescript`. The scripts are loaded and executed in order on page
+# load.
 runScripts = ->
-  for script in document.getElementsByTagName 'script'
-    if script.type is 'text/coffeescript'
-      if script.src
-        CoffeeScript.load script.src
-      else
-        CoffeeScript.run script.innerHTML
+  scripts = document.getElementsByTagName 'script'
+  index = 0
+  length = scripts.length
+  (execute = (error) ->
+    throw error if error
+    script = scripts[index++]
+    if script.type is 'text/coffeescript' and script.src
+      CoffeeScript.load script.src, null, execute
+    else
+      CoffeeScript.run script.innerHTML
+      execute()
+  )()
   null
 
-# Listen for window load, both in browsers and in IE.
-if window.addEventListener
-  addEventListener 'DOMContentLoaded', runScripts, no
-else
-  attachEvent 'onload', runScripts
+# Execute scripts on page load in W3C-compliant browsers and IE.
+if typeof @addEventListener isnt 'undefined'
+  @addEventListener 'DOMContentLoaded', runScripts, no
+else if typeof @attachEvent isnt 'undefined'
+  @attachEvent 'onload', runScripts