Fixes: module "process"; chrome.runtime.lastError

- Added a 'require' to pull process into the background page.  May fix
  the issue identified at
  #100 (comment) .
- More sophisticated stringification of chrome.runtime.lastError.
  Somewhere around Chrome 75, chrome.runtime.lastError lost toString(),
  as far as I can tell.

app/bg/background.js

@@ -5,6 +5,13 @@ console.log('TabFern: running ' + __filename);
 if(false) { // Vendor files - listed here only so they'll be bundled
     require('vendor/validation');
     require('vendor/common');
+
+    // The following require() seems to fix the 'cannot find module "process"
+    // from "/"' error mentioned at
+    // https://github.com/cxw42/TabFern/issues/100#issuecomment-450058252
+    // and discussed further at
+    // https://github.com/cxw42/TabFern/issues/100#issuecomment-513267574 .
+    require('process/browser');
 }
 
 const S = require('common/setting-definitions');    // in app/
@@ -144,7 +151,7 @@ function editNoteOnClick(info, tab)
         function(resp){
             if(isLastError()) {
                 console.log('Couldn\'t send edit-note to ' + tab.id + ': ' +
-                    chrome.runtime.lastError);
+                    lastBrowserErrorMessageString());
             } else {
                 console.log({[`response to edit-note for ${tab.id}`]: resp});
             }

app/win/main_tl.js

@@ -442,7 +442,7 @@ function saveTree(save_ephemeral_windows = true, cbk = undefined)
                 return;     // Saved OK
             }
             //else there was an error
-            let msg = _T('errCouldNotSave', chrome.runtime.lastError.toString());
+            let msg = _T('errCouldNotSave', lastBrowserErrorMessageString());
             log.error(msg);
             window.alert(msg);     // The user needs to know
             if(typeof cbk === 'function') cbk(new Error(msg));
@@ -561,7 +561,7 @@ function flagOnlyCurrentTabCC(cwin)
     if(!isLastError()) {
         flagOnlyCurrentTab(cwin);
     } else {
-        log.info({"Couldn't flag": chrome.runtime.lastError});
+        log.info({"Couldn't flag": lastBrowserErrorMessageString()});
     }
 } //flagOnlyCurrentTabCC
 
@@ -1710,7 +1710,7 @@ function loadSavedWindowsIntoTree(next_action) {
         READIT:
         if(isLastError()) {
             //Chrome couldn't load the data
-            log.error("Chrome couldn't load save data: " + chrome.runtime.lastError +
+            log.error("Chrome couldn't load save data: " + lastBrowserErrorMessageString() +
                     "\nHowever, if you didn't have any save data, this isn't " +
                     "a problem!");
 
@@ -1745,7 +1745,7 @@ function DBG_printSaveData()
 {
     chrome.storage.local.get(K.STORAGE_KEY, function(items) {
         if(isLastError()) {
-            console.log(chrome.runtime.lastError);
+            console.log(lastBrowserErrorMessageString());
         } else {
             let parsed = items[K.STORAGE_KEY];
             console.log('Save data:');
@@ -2005,7 +2005,7 @@ function treeOnSelect(evt_unused, evt_data, options={})
 
             if(isLastError()) {
                 window.alert(_T('errCouldNotOpenWindow',
-                                    chrome.runtime.lastError));
+                                    lastBrowserErrorMessageString()));
                 return;     // with the state in the tree unchanged
             }
 
@@ -4322,7 +4322,7 @@ function moveWinToLastPositionIfAny_catch(done, items_or_err)
         chrome.windows.update(my_winid, size_data,
             (win)=>{
                 if(isLastError()) {
-                    log.error(`Could not move window: ${chrome.runtime.lastError}`);
+                    log.error(`Could not move window: ${lastBrowserErrorMessageString()}`);
                 } else {
                     log.info({"Updated window size":$.extend({},win)});
                 }

package.json

@@ -1,6 +1,6 @@
 {
   "name": "tabfern",
-  "version": "0.2.1-pre.1",
+  "version": "0.2.1-pre.2",
   "description": "Google Chrome extension for displaying, saving, and managing tabs",
   "main": "src/view/main.js",
   "directories": {
@@ -46,6 +46,7 @@
     "keypress.js": "^2.1.5",
     "loglevel": "^1.6.1",
     "path-browserify": "^1.0.0",
+    "process": "*",
     "requirejs": "^2.3.5",
     "rmodal": "^1.0.33",
     "signals": "^1.0.0",

vendor/common.js

@@ -17,7 +17,7 @@ const MSG_GET_VIEW_WIN_ID = 'getViewWindowID';
 const MSG_EDIT_TAB_NOTE = 'editTabNote';
 
 ////////////////////////////////////////////////////////////////////////// }}}1
-// Test for Firefox // {{{1
+// Cross-browser error handling, and browser tests // {{{1
 // Not sure if I need this, but I'm playing it safe for now.  Firefox returns
 // null rather than undefined in chrome.runtime.lastError when there is
 // no error.  This is to test for null in Firefox without changing my
@@ -54,6 +54,27 @@ BROWSER_TYPE=null;  // unknown
     }
 })(window);
 
+/// Return a string representation of chrome.runtime.lastError.
+///
+/// Somewhere around Chrome 75, chrome.runtime.lastError lost toString(),
+/// as far as I can tell.
+/// See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error
+///     https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API/runtime/lastError
+///     https://developer.chrome.com/extensions/runtime#property-lastError
+function lastBrowserErrorMessageString() {
+    if(!chrome.runtime.lastError) {
+        return "<no error>";
+    }
+
+    if(typeof chrome.runtime.lastError !== 'object') {
+        return `${chrome.runtime.lastError}`;
+    }
+
+    return chrome.runtime.lastError.message ||
+            chrome.runtime.lastError.description ||
+            chrome.runtime.lastError.toString();
+}
+
 ////////////////////////////////////////////////////////////////////////// }}}1
 // DOM-related functions // {{{1