sendMessage()

Promise mode [default]:
  - rejects on receiving {__ERROR__: message} created by
    background.js::onRuntimeMessage
  - suppresses chrome.runtime.lastError
    by browserAction.setText which lacks a callback param in chrome API

Callback mode:
  - enabled by passing a second param
  - doesn't suppress chrome.runtime.lastError

.eslintrc

@@ -17,6 +17,7 @@ globals:
   URLS: false
   BG: false
   notifyAllTabs: false
+  sendMessage: false
   queryTabs: false
   getTab: false
   getOwnTab: false

background/background.js

@@ -110,7 +110,7 @@ contextMenus = Object.assign({
     contexts: ['editable'],
     documentUrlPatterns: [URLS.ownOrigin + 'edit*'],
     click: (info, tab) => {
-      chrome.tabs.sendMessage(tab.id, {method: 'editDeleteText'});
+      sendMessage(tab.id, {method: 'editDeleteText'});
     },
   }
 });
@@ -179,15 +179,12 @@ window.addEventListener('storageReady', function _() {
   };
 
   const pingCS = (cs, {id, url}) => {
+    const maybeInject = pong => !pong && injectCS(cs, PING.tabId);
     cs.matches.some(match => {
-      if ((match === ALL_URLS || url.match(match))
-        && (!url.startsWith('chrome') || url === NTP)) {
-        chrome.tabs.sendMessage(id, PING, pong => {
-          if (!pong) {
-            injectCS(cs, id);
-          }
-          ignoreChromeError();
-        });
+      if ((match === ALL_URLS || url.match(match)) &&
+          (!url.startsWith('chrome') || url === NTP)) {
+        PING.tabId = id;
+        sendMessage(PING).then(maybeInject);
         return true;
       }
     });
@@ -211,13 +208,13 @@ function webNavigationListener(method, {url, tabId, frameId}) {
       if (method === 'styleApply') {
         handleCssTransitionBug({tabId, frameId, url, styles});
       }
-      chrome.tabs.sendMessage(tabId, {
+      sendMessage({
+        tabId,
+        frameId,
         method,
         // ping own page so it retrieves the styles directly
         styles: url.startsWith(URLS.ownOrigin) ? 'DIY' : styles,
-      }, {
-        frameId
-      }, ignoreChromeError);
+      });
     }
     // main page frame id is 0
     if (frameId === 0) {
@@ -303,9 +300,15 @@ function updateIcon(tab, styles) {
 }
 
 
-function onRuntimeMessage(request, sender, sendResponse) {
-  // prevent browser exception bug on sending a response to a closed tab
-  sendResponse = (send => data => tryCatch(send, data))(sendResponse);
+function onRuntimeMessage(request, sender, sendResponseInternal) {
+  const sendResponse = data => {
+    // wrap Error object instance as {__ERROR__: message} - will be unwrapped in sendMessage
+    if (data instanceof Error) {
+      data = {__ERROR__: data.message};
+    }
+    // prevent browser exception bug on sending a response to a closed tab
+    tryCatch(sendResponseInternal, data);
+  };
   switch (request.method) {
     case 'getStyles':
       getStyles(request).then(sendResponse);
@@ -353,6 +356,7 @@ function onRuntimeMessage(request, sender, sendResponse) {
   }
 }
 
+
 function closeTab(tabId, request) {
   return new Promise(resolve => {
     if (request.tabId) {

background/usercss-helper.js

@@ -23,11 +23,7 @@ var usercssHelper = (() => {
 
   function wrapReject(pending) {
     return pending
-      .then(result => ({success: true, result}))
-      .catch(err => ({
-        success: false,
-        result: Array.isArray(err) ? err.join('\n') : err.message || String(err),
-      }));
+      .catch(err => new Error(Array.isArray(err) ? err.join('\n') : err.message || String(err)));
   }
 
   // Parse the source and find the duplication

content/install-hook-usercss.js

@@ -1,4 +1,3 @@
-/* global runtimeSend */
 'use strict';
 
 function createSourceLoader() {
@@ -95,16 +94,16 @@ function initUsercssInstall() {
           if (history.length > 1) {
             history.back();
           } else {
-            runtimeSend({method: 'closeTab'});
+            chrome.runtime.sendMessage({method: 'closeTab'});
           }
           break;
       }
     });
   });
-  return runtimeSend({
+  chrome.runtime.sendMessage({
     method: 'openUsercssInstallPage',
-    updateUrl: location.href
-  }).catch(alert);
+    updateUrl: location.href,
+  }, r => r && r.__ERROR__ && alert(r.__ERROR__));
 }
 
 function isUsercss() {

content/util.js

@@ -1,10 +0,0 @@
-'use strict';
-
-function runtimeSend(request) {
-  return new Promise((resolve, reject) => {
-    chrome.runtime.sendMessage(
-      request,
-      ({success, result}) => (success ? resolve : reject)(result)
-    );
-  });
-}

install-usercss.html

@@ -85,7 +85,6 @@
       <div class="warnings"></div>
     </div>
   </div>
-  <script src="/content/util.js"></script>
   <script src="/install-usercss/install-usercss.js"></script>
 </body>
 </html>

install-usercss/install-usercss.js

@@ -1,4 +1,4 @@
-/* global CodeMirror semverCompare makeLink closeCurrentTab runtimeSend */
+/* global CodeMirror semverCompare makeLink closeCurrentTab */
 /* global messageBox */
 'use strict';
 
@@ -44,7 +44,7 @@
       cm.setCursor(cursor);
       cm.scrollTo(scrollInfo.left, scrollInfo.top);
 
-      return runtimeSend({
+      return sendMessage({
         id: installed.id,
         method: 'saveUsercss',
         reason: 'update',
@@ -168,50 +168,36 @@
   }
 
   function install(style) {
-    const request = Object.assign(style, {
-      method: 'saveUsercss',
-      reason: 'update'
-    });
-    return runtimeSend(request)
-      .then(result => {
-        installed = result;
+    installed = style;
 
-        $$('.warning')
-          .forEach(el => el.remove());
-        $('.install').disabled = true;
-        $('.install').classList.add('installed');
-        $('.set-update-url input[type=checkbox]').disabled = true;
-        $('.set-update-url').title = result.updateUrl ?
-          t('installUpdateFrom', result.updateUrl) : '';
+    $$('.warning')
+      .forEach(el => el.remove());
+    $('.install').disabled = true;
+    $('.install').classList.add('installed');
+    $('.set-update-url input[type=checkbox]').disabled = true;
+    $('.set-update-url').title = style.updateUrl ?
+      t('installUpdateFrom', style.updateUrl) : '';
 
-        updateMeta(result);
+    updateMeta(style);
 
-        chrome.runtime.sendMessage({method: 'openEditor', id: result.id});
+    sendMessage({method: 'openEditor', id: style.id});
 
-        if (!liveReload) {
-          port.postMessage({method: 'closeTab'});
-        }
+    if (!liveReload) {
+      port.postMessage({method: 'closeTab'});
+    }
 
-        window.dispatchEvent(new CustomEvent('installed'));
-      })
-      .catch(err => {
-        messageBox.alert(chrome.i18n.getMessage('styleInstallFailed', String(err)));
-      });
+    window.dispatchEvent(new CustomEvent('installed'));
   }
 
   function initSourceCode(sourceCode) {
     cm.setValue(sourceCode);
     cm.refresh();
-    runtimeSend({
-      method: 'buildUsercss',
-      sourceCode,
-      checkDup: true
-    }).then(init, onInitError);
-  }
-
-  function onInitError(err) {
-    $('.header').classList.add('meta-init-error');
-    showError(err);
+    sendMessage({method: 'buildUsercss', sourceCode, checkDup: true})
+      .then(init)
+      .catch(err => {
+        $('.header').classList.add('meta-init-error');
+        showError(err);
+      });
   }
 
   function buildWarning(err) {
@@ -236,17 +222,14 @@
       );
     }
     $('button.install').onclick = () => {
-      const message = dup ?
-        chrome.i18n.getMessage('styleInstallOverwrite', [
-          data.name, dupData.version, data.version
-        ]) :
-        chrome.i18n.getMessage('styleInstall', [data.name]);
-
-      messageBox.confirm(message).then(result => {
-        if (result) {
-          return install(style);
-        }
-      });
+      messageBox.confirm(dup ?
+        t('styleInstallOverwrite', [data.name, dupData.version, data.version]) :
+        t('styleInstall', [data.name])
+      ).then(ok => ok &&
+        sendMessage(Object.assign(style, {method: 'saveUsercss', reason: 'update'}))
+          .then(install)
+          .catch(err => messageBox.alert(t('styleInstallFailed', err)))
+      );
     };
 
     // set updateUrl

js/messaging.js

@@ -87,7 +87,6 @@ function notifyAllTabs(msg) {
       style: getStyleWithNoCode(msg.style)
     });
   }
-  const maybeIgnoreLastError = FIREFOX ? ignoreChromeError : undefined;
   const affectsAll = !msg.affects || msg.affects.all;
   const affectsOwnOriginOnly = !affectsAll && (msg.affects.editor || msg.affects.manager);
   const affectsTabs = affectsAll || affectsOwnOriginOnly;
@@ -101,7 +100,8 @@ function notifyAllTabs(msg) {
       && !(affectsSelf && tab.url.startsWith(URLS.ownOrigin))
       // skip lazy-loaded aka unloaded tabs that seem to start loading on message in FF
       && (!FIREFOX || tab.width)) {
-        chrome.tabs.sendMessage(tab.id, msg, maybeIgnoreLastError);
+        msg.tabId = tab.id;
+        sendMessage(msg, ignoreChromeError);
       }
       if (affectsIcon && BG) {
         BG.updateIcon(tab);
@@ -128,7 +128,34 @@ function notifyAllTabs(msg) {
   }
   // notify background page and all open popups
   if (affectsSelf) {
-    chrome.runtime.sendMessage(msg, maybeIgnoreLastError);
+    msg.tabId = null;
+    sendMessage(msg, ignoreChromeError);
+  }
+}
+
+
+function sendMessage(msg, callback) {
+  /*
+  Promise mode [default]:
+    - rejects on receiving {__ERROR__: message} created by background.js::onRuntimeMessage
+    - automatically suppresses chrome.runtime.lastError because it's autogenerated
+      by browserAction.setText which lacks a callback param in chrome API
+  Standard callback mode:
+    - enabled by passing a second param
+  */
+  const {tabId, frameId} = msg;
+  const fn = tabId ? chrome.tabs.sendMessage : chrome.runtime.sendMessage;
+  const args = tabId ? [tabId, msg, {frameId}] : [msg];
+  if (callback) {
+    fn(...args, callback);
+  } else {
+    return new Promise((resolve, reject) => {
+      fn(...args, r => {
+        const err = r && r.__ERROR__;
+        (err ? reject : resolve)(err || r);
+        chrome.runtime.lastError; // eslint-disable-line no-unused-expressions
+      });
+    });
   }
 }
 
@@ -338,7 +365,7 @@ function sessionStorageHash(name) {
 
 function onBackgroundReady() {
   return BG && BG.getStyles ? Promise.resolve() : new Promise(function ping(resolve) {
-    chrome.runtime.sendMessage({method: 'healthCheck'}, health => {
+    sendMessage({method: 'healthCheck'}, health => {
       if (health !== undefined) {
         BG = chrome.extension.getBackgroundPage();
         resolve();

manage/fileSaveLoad.js

@@ -288,8 +288,8 @@ function importFromString(jsonString) {
             if (tab.id === ownTab.id) {
               applyOnMessage(message);
             } else {
-              invokeOrPostpone(tab.id === activeTab.id,
-                chrome.tabs.sendMessage, tab.id, message, ignoreChromeError);
+              message.tabId = tab.id;
+              invokeOrPostpone(tab.id === activeTab.id, sendMessage, message, ignoreChromeError);
             }
             setTimeout(BG.updateIcon, 0, tab, styles);
             if (tab === lastTab) {

manage/manage.js

@@ -581,10 +581,10 @@ function dieOnNullBackground() {
   if (!FIREFOX || BG) {
     return;
   }
-  chrome.runtime.sendMessage({method: 'healthCheck'}, health => {
+  sendMessage({method: 'healthCheck'}, health => {
     if (health && !chrome.extension.getBackgroundPage()) {
       onDOMready().then(() => {
-        chrome.runtime.sendMessage({method: 'getStyles'}, showStyles);
+        sendMessage({method: 'getStyles'}, showStyles);
         messageBox({
           title: 'Stylus',
           className: 'danger center',

manifest.json

@@ -54,14 +54,14 @@
       "matches": ["http://userstyles.org/*", "https://userstyles.org/*"],
       "run_at": "document_start",
       "all_frames": false,
-      "js": ["content/install.js"]
+      "js": ["content/install-hook-userstyles.js"]
     },
     {
       "matches": ["<all_urls>"],
       "include_globs": ["*.user.css", "*.user.styl"],
       "run_at": "document_idle",
       "all_frames": false,
-      "js": ["content/util.js", "content/install-user-css.js"]
+      "js": ["content/install-hook-usercss.js"]
     }
   ],
   "browser_action": {

popup/popup.js

@@ -119,7 +119,7 @@ function initPopup(url) {
   }
 
   getActiveTab().then(function ping(tab, retryCountdown = 10) {
-    chrome.tabs.sendMessage(tab.id, {method: 'ping'}, {frameId: 0}, pong => {
+    sendMessage({tabId: tab.id, method: 'ping', frameId: 0}, pong => {
       if (pong) {
         return;
       }