prepare 3.2.6 release (#21)

Author: LaunchDarklyCI

src/__tests__/ConsoleLogger-test.js

@@ -93,6 +93,25 @@ describe('createConsoleLogger', () => {
         expect(infoSpy).not.toHaveBeenCalled();
         expect(warnSpy).not.toHaveBeenCalled();
       });
+
+      it('does not throw an error if console is undefined or null', () => {
+        // see comments in ConsoleLogger.js
+        const oldConsole = console;
+        try {
+          console = null; // eslint-disable-line no-global-assign
+          logger.debug('x');
+          logger.info('x');
+          logger.warn('x');
+          logger.error('x');
+          console = undefined; // eslint-disable-line no-global-assign
+          logger.debug('x');
+          logger.info('x');
+          logger.warn('x');
+          logger.error('x');
+        } finally {
+          console = oldConsole; // eslint-disable-line no-global-assign
+        }
+      });
     });
   });
 });

src/consoleLogger.js

@@ -2,6 +2,10 @@
 // If no minimum level is specified, all messages will be logged. Setting the level to "none"
 // disables all logging.
 
+// Note that the global console variable is not guaranteed to be defined at all times in all
+// browsers, so this implementation checks for its existence at the time a message is logged.
+// See: https://www.beyondjava.net/console-log-surprises-with-internet-explorer-11-and-edge
+
 export default function createConsoleLogger(level, maybePrefix) {
   const allLevels = ['debug', 'info', 'warn', 'error'];
   let prefix;
@@ -21,17 +25,20 @@ export default function createConsoleLogger(level, maybePrefix) {
 
   const logger = {};
 
-  function log(levelIndex, outputFn, msg) {
-    if (levelIndex >= minLevelIndex) {
-      const levelName = levelIndex < allLevels.length ? allLevels[levelIndex] : '?';
-      outputFn(prefix + '[' + levelName + '] ' + msg);
+  function log(levelIndex, methodName, msg) {
+    if (levelIndex >= minLevelIndex && console) {
+      const method = console[methodName];
+      if (method) {
+        const levelName = levelIndex < allLevels.length ? allLevels[levelIndex] : '?';
+        method.call(console, prefix + '[' + levelName + '] ' + msg);
+      }
     }
   }
 
-  logger.debug = msg => log(0, console.log, msg); // eslint-disable-line no-console
-  logger.info = msg => log(1, console.info, msg); // eslint-disable-line no-console
-  logger.warn = msg => log(2, console.warn, msg); // eslint-disable-line no-console
-  logger.error = msg => log(3, console.error, msg); // eslint-disable-line no-console
+  logger.debug = msg => log(0, 'log', msg); // eslint-disable-line no-console
+  logger.info = msg => log(1, 'info', msg); // eslint-disable-line no-console
+  logger.warn = msg => log(2, 'warn', msg); // eslint-disable-line no-console
+  logger.error = msg => log(3, 'error', msg); // eslint-disable-line no-console
 
   return logger;
 }