change logic so that instead of using catches, a background script is…

… used to check for already injected scripts. Now works with firefox

GPTrueOrFalse/src/background/background.js

@@ -0,0 +1,21 @@
+// initialize object containing ids of tabs who have been injected
+let injected = {};
+browser.runtime.onMessage.addListener(gotMessage);
+function gotMessage(message) {
+  console.log(injected);
+  if (message.type === "get-injected") {
+    return Promise.resolve(injected);
+  } else if (message.type === "injection-update") {
+    if (message.content.task === "append") {
+      injected[message.content.value] = true;
+    } else if (message.content.task === "delete") {
+      delete injected[message.content.value];
+    }
+  }
+}
+
+// remove tabs from injected obj when they are closed
+browser.tabs.onRemoved.addListener(handleRemoved);
+function handleRemoved(tabId) {
+  if (injected[tabId]) delete injected[tabId];
+}

GPTrueOrFalse/src/content/content.js

@@ -11,8 +11,6 @@ function gotMessage(message) {
     return checkSelection();
   } else if (message.type === "evaluate") {
     return evaluateSelection();
-  } else if (message.type === "loaded-check") {
-    return Promise.resolve({ reply: true });
   }
 }
 
@@ -89,7 +87,7 @@ function getSelectedText() {
   return text;
 }
 
-// generates HSL string given on a percentage between a start and end color
+// generates HSL string given a percentage between a start and end color
 function generateHSLString(percent, start, end) {
   let fraction = percent / 100;
   let offset = (end - start) * fraction;

GPTrueOrFalse/src/manifest.json

@@ -24,5 +24,11 @@
     },
     "default_popup": "popup/index.html",
     "default_title": "GPTrue or False"
+  },
+  "background": {
+    "scripts": [
+      "./libraries/browser-polyfill.min.js",
+      "./background/background.js"
+    ]
   }
 }

GPTrueOrFalse/src/popup/index.js

@@ -1,33 +1,43 @@
 window.onload = () => {
-  // get the current tab
+  //check if the ask background script for list of tabs with loaded
   return (
-    browser.tabs
-      .query({ active: true, currentWindow: true })
-      .then(query_result => {
-        // ask it if the content script is already loaded
-        return browser.tabs.sendMessage(query_result[0].id, {
-          type: "loaded-check"
-        });
-      })
-      .then(res => {
-        // if it is, do nothing for this promise
-        if (res) return Promise.resolve();
-      })
-      .catch(() => {
-        // an error being thrown signals the content script not being loaded, load it.
+    browser.runtime
+      .sendMessage({ type: "get-injected" })
+      .then(injected_obj => {
         return browser.tabs
-          .executeScript({
-            file: "./libraries/jquery-3.3.1.slim.min.js"
-          })
-          .then(() => {
-            return browser.tabs.executeScript({
-              file: "./libraries/browser-polyfill.min.js"
-            });
-          })
-          .then(() => {
-            return browser.tabs.executeScript({
-              file: "./content/content.js"
-            });
+          .query({ active: true, currentWindow: true })
+          .then(query_result => {
+            let current_tab_id = query_result[0].id;
+            // if the current tab has already been injected
+            if (injected_obj[current_tab_id]) {
+              return Promise.resolve();
+            } else {
+              // update the injected list in the background script
+              return browser.runtime
+                .sendMessage({
+                  type: "injection-update",
+                  content: {
+                    task: "append",
+                    value: current_tab_id
+                  }
+                })
+                .then(() => {
+                  // inject the necessary scripts otherwise.
+                  return browser.tabs.executeScript({
+                    file: "/libraries/jquery-3.3.1.slim.min.js"
+                  });
+                })
+                .then(() => {
+                  return browser.tabs.executeScript({
+                    file: "/libraries/browser-polyfill.min.js"
+                  });
+                })
+                .then(() => {
+                  return browser.tabs.executeScript({
+                    file: "/content/content.js"
+                  });
+                });
+            }
           });
       })
       // check that enough words are selected
@@ -48,6 +58,7 @@ window.onload = () => {
           return deactivateButton("evaluateSelectedText", selected_words);
         }
       })
+      .catch(err => console.log(err))
   );
 };