Fix evalScripts() (#186)

* Set the id of the inserted <script>.
* Check if the <script> still exists before trying to remove it.

lib/eval-script.js

@@ -12,6 +12,7 @@ module.exports = function(el) {
   }
 
   script.type = "text/javascript"
+  script.id = el.id;
 
   /* istanbul ignore if */
   if (src !== "") {
@@ -33,7 +34,7 @@ module.exports = function(el) {
   // execute
   parent.appendChild(script)
   // avoid pollution only in head or body tags
-  if (parent instanceof HTMLHeadElement || parent instanceof HTMLBodyElement) {
+  if ((parent instanceof HTMLHeadElement || parent instanceof HTMLBodyElement) && parent.contains(script)) {
     parent.removeChild(script)
   }
 

tests/lib/eval-scripts.js

@@ -21,3 +21,21 @@ tape("test evalScript method", function(t) {
 
   t.end()
 })
+
+tape("evalScript should not throw an error if the script removed itself", function(t) {
+  var script = document.createElement("script")
+  script.id = "myScript";
+  script.innerHTML = "const script = document.querySelector('#myScript');" +
+    "script.parentNode.removeChild(script);";
+
+  try {
+    evalScript(script);
+
+    t.pass("Missing script tested successfully");
+  } catch (e) {
+    console.error(e);
+    t.fail("Attempted to remove missing script");
+  }
+
+  t.end();
+})