Allow regex in blacklist fixes #167 #542 (#546)

* Allow regex in blacklist fixes #167 #542
* Added protection against invalid regex causing failed initialization
* Added regex input validation

inject.js

@@ -292,7 +292,16 @@
         return;
       }
 
+      if (match.startsWith('/')) {
+        try {
+          var regexp = new RegExp(match);
+        } catch(err) {
+          return;
+        }
+      } else {
         var regexp = new RegExp(escapeStringRegExp(match));
+      }
+
       if (regexp.test(location.href)) {
         blacklisted = true;
         return;

options.html

@@ -109,7 +109,12 @@
         <input id="controllerOpacity" type="text" value="">
       </div>
       <div class="row">
-        <label for="blacklist">Blacklisted sites on which extension is disabled<br/>(one per line)</label>
+        <label for="blacklist">Blacklisted sites on which extension is disabled<br/>
+            (one per line)<br/>
+            <br/>
+            <em><a href="https://www.regexpal.com/">Regex</a> is supported. Be sure it is in "//g" format.<br/>
+            ie: /(.+)youtube\.com(\/*)$/gi</em>
+        </label>
         <textarea id="blacklist" rows="10" cols="50"></textarea>
       </div>
     </section>

options.js

@@ -163,8 +163,31 @@ function createKeyBindings(item) {
   keyBindings.push({action: action, key: key, value: value, force: force, predefined: predefined});
 }
 
+// Validates settings before saving
+function validate() {
+  var valid = true;
+  var status = document.getElementById('status');
+  document.getElementById('blacklist').value.split("\n").forEach(match => {
+    match = match.replace(regStrip,'')
+    if (match.startsWith('/')) {
+      try {
+        var regexp = new RegExp(match);
+      } catch(err) {
+        status.textContent = 'Error: Invalid Regex: ' + match
+                           + '. Unable to save';
+        valid = false;
+        return;
+      }
+    }
+  })
+  return valid;
+}
+
 // Saves options to chrome.storage
 function save_options() {
+  if (validate() === false) {
+    return;
+  }
   keyBindings = [];
   Array.from(document.querySelectorAll(".customs")).forEach(item => createKeyBindings(item)); // Remove added shortcuts