Change (un)install changes to only work for >57. Fixes #858 and Fixes #900

bootstrap.js

@@ -130,9 +130,16 @@ async function install() {
 }
 
 // eslint-disable-next-line no-unused-vars
-async function uninstall(aData, aReason) {
+async function uninstall({resourceURI}, aReason) {
-  if (aReason === ADDON_UNINSTALL
+  if (checkLegacyFirefox()) {
-      || aReason === ADDON_DISABLE) {
+    if (aReason === ADDON_UNINSTALL) {
+      unloadStyles(resourceURI);
+      await removeChanges();
+    }
+  }
+}
+
+async function removeChanges() {
   const config = await getConfig();
   const storedPrefs = config.savedConfiguration.prefs || {};
   PREFS.forEach((pref) => {
@@ -147,24 +154,34 @@ async function uninstall(aData, aReason) {
     }
   });
 }
+
+function checkLegacyFirefox() {
+  const version = Services.appinfo.version;
+  const versionMatch = version.match(/^([0-9]+)\./)[1];
+  if (Number(versionMatch) <= 56) {
+    return true;
+  }
+  return false;
 }
 
 // eslint-disable-next-line no-unused-vars
 function startup({webExtension, resourceURI}) {
-  const version = Services.appinfo.version;
+  if (checkLegacyFirefox()) {
-  const versionMatch = version.match(/^([0-9]+)\./)[1];
-  if (versionMatch === "55"
-      || versionMatch === "56") {
     loadStyles(resourceURI);
-  }
     // Reset prefs that may have changed, or are legacy
     install();
+  }
   // Start the embedded webextension.
   webExtension.startup();
 }
 
 // eslint-disable-next-line no-unused-vars
-function shutdown({resourceURI}) {
+function shutdown({resourceURI}, aReason) {
+  if (checkLegacyFirefox()) {
     unloadStyles(resourceURI);
+    if (aReason === ADDON_DISABLE) {
+      removeChanges();
+    }
+  }
 }