For the ES module version of the browser compiler, don't automaticall…

…y attach the runScripts event handler
jashkenas · Mar 25, 2019 · ad7505f · ad7505f
1 parent 3c6d609
commit ad7505f
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Showing 7 changed files with 42 additions and 18 deletions.
diff --git a/docs/v2/annotated-source/browser.html b/docs/v2/annotated-source/browser.html
@@ -321,14 +321,19 @@ <h1>browser.coffee</h1>
               <div class="pilwrap ">
                 <a class="pilcrow" href="#section-10">&#182;</a>
               </div>
-              <p>Listen for window load, both in decent browsers and in IE.</p>
+              <p>Listen for window load, both in decent browsers and in IE.
+Only attach this event handler on startup for the
+non-ES module version of the browser compiler, to preserve
+backward compatibility while letting the ES module version
+be importable without side effects.</p>
 
             </div>
 
-            <div class="content"><div class='highlight'><pre><span class="hljs-keyword">if</span> <span class="hljs-built_in">window</span>.addEventListener
-  <span class="hljs-built_in">window</span>.addEventListener <span class="hljs-string">'DOMContentLoaded'</span>, CoffeeScript.runScripts, <span class="hljs-literal">no</span>
-<span class="hljs-keyword">else</span>
-  <span class="hljs-built_in">window</span>.attachEvent <span class="hljs-string">'onload'</span>, CoffeeScript.runScripts</pre></div></div>
+            <div class="content"><div class='highlight'><pre><span class="hljs-keyword">if</span> <span class="hljs-keyword">this</span> <span class="hljs-keyword">is</span> <span class="hljs-built_in">window</span>
+  <span class="hljs-keyword">if</span> <span class="hljs-built_in">window</span>.addEventListener
+    <span class="hljs-built_in">window</span>.addEventListener <span class="hljs-string">'DOMContentLoaded'</span>, CoffeeScript.runScripts, <span class="hljs-literal">no</span>
+  <span class="hljs-keyword">else</span>
+    <span class="hljs-built_in">window</span>.attachEvent <span class="hljs-string">'onload'</span>, CoffeeScript.runScripts</pre></div></div>
 
         </li>
 

diff --git a/docs/v2/browser-compiler-modern/coffeescript.js b/docs/v2/browser-compiler-modern/coffeescript.js
@@ -11200,10 +11200,16 @@ if (typeof module !== 'undefined' && require.main === module) {
   };
 
   // Listen for window load, both in decent browsers and in IE.
-  if (window.addEventListener) {
-    window.addEventListener('DOMContentLoaded', CoffeeScript.runScripts, false);
-  } else {
-    window.attachEvent('onload', CoffeeScript.runScripts);
+  // Only attach this event handler on startup for the
+  // non-ES module version of the browser compiler, to preserve
+  // backward compatibility while letting the ES module version
+  // be importable without side effects.
+  if (this === window) {
+    if (window.addEventListener) {
+      window.addEventListener('DOMContentLoaded', CoffeeScript.runScripts, false);
+    } else {
+      window.attachEvent('onload', CoffeeScript.runScripts);
+    }
   }
 
 }).call(this);

diff --git a/docs/v2/browser-compiler/coffeescript.js b/docs/v2/browser-compiler/coffeescript.js
diff --git a/docs/v2/test.html b/docs/v2/test.html
@@ -7,6 +7,7 @@
   <script type="module">
     import CoffeeScript from './browser-compiler-modern/coffeescript.js';
     window.CoffeeScript = CoffeeScript;
+    window.addEventListener('DOMContentLoaded', CoffeeScript.runScripts, false);
   </script>
   <script src="https://cdn.jsdelivr.net/underscorejs/1.8.3/underscore-min.js"></script>
   <style>

diff --git a/documentation/site/test.html b/documentation/site/test.html
@@ -7,6 +7,7 @@
   <script type="module">
     import CoffeeScript from './browser-compiler-modern/coffeescript.js';
     window.CoffeeScript = CoffeeScript;
+    window.addEventListener('DOMContentLoaded', CoffeeScript.runScripts, false);
   </script>
   <script src="https://cdn.jsdelivr.net/underscorejs/1.8.3/underscore-min.js"></script>
   <style>

diff --git a/lib/coffeescript/browser.js b/lib/coffeescript/browser.js
diff --git a/src/browser.coffee b/src/browser.coffee
@@ -96,7 +96,12 @@ CoffeeScript.runScripts = ->
   execute()
 
 # Listen for window load, both in decent browsers and in IE.
-if window.addEventListener
-  window.addEventListener 'DOMContentLoaded', CoffeeScript.runScripts, no
-else
-  window.attachEvent 'onload', CoffeeScript.runScripts
+# Only attach this event handler on startup for the
+# non-ES module version of the browser compiler, to preserve
+# backward compatibility while letting the ES module version
+# be importable without side effects.
+if this is window
+  if window.addEventListener
+    window.addEventListener 'DOMContentLoaded', CoffeeScript.runScripts, no
+  else
+    window.attachEvent 'onload', CoffeeScript.runScripts