chore(refactor): using writer.writable instead of alive for checking

lib/appenders/dateFile.js

@@ -3,13 +3,29 @@ const os = require('os');
 
 const eol = os.EOL;
 
+function openTheStream(filename, pattern, options) {
+  const stream = new streams.DateRollingFileStream(
+    filename,
+    pattern,
+    options
+  );
+  stream.on('error', (err) => {
+    console.error('log4js.dateFileAppender - Writing to file %s, error happened ', filename, err); //eslint-disable-line
+  });
+  stream.on("drain", () => {
+    process.emit("log4js:pause", false);
+  });
+  return stream;
+}
+
 /**
  * File appender that rolls files according to a date pattern.
- * @filename base filename.
- * @pattern the format that will be added to the end of filename when rolling,
+ * @param filename base filename.
+ * @param pattern the format that will be added to the end of filename when rolling,
  *          also used to check when to roll files - defaults to '.yyyy-MM-dd'
- * @layout layout function for log messages - defaults to basicLayout
- * @timezoneOffset optional timezone offset in minutes - defaults to system local
+ * @param layout layout function for log messages - defaults to basicLayout
+ * @param options - options to be passed to the underlying stream
+ * @param timezoneOffset - optional timezone offset in minutes (default system local)
  */
 function appender(
   filename,
@@ -22,35 +38,19 @@ function appender(
   // options should work for dateFile as well.
   options.maxSize = options.maxLogSize;
 
-  let alive = true;
-
-  const logFile = new streams.DateRollingFileStream(
-    filename,
-    pattern,
-    options
-  );
-
-  logFile.on('error', (err) => {
-    alive = false;
-    console.error('log4js.dateFileAppender - Writing to file %s, error happened ', filename, err); //eslint-disable-line
-  });
-  logFile.on("drain", () => {
-    process.emit("log4js:pause", false);
-  });
+  const writer = openTheStream(filename, pattern, options);
 
   const app = function (logEvent) {
-    if (!alive) {
+    if (!writer.writable) {
       return;
     }
-    if (!logFile.write(layout(logEvent, timezoneOffset) + eol, "utf8")) {
+    if (!writer.write(layout(logEvent, timezoneOffset) + eol, "utf8")) {
       process.emit("log4js:pause", true);
     }
   };
 
   app.shutdown = function (complete) {
-    logFile.write('', 'utf-8', () => {
-      logFile.end(complete);
-    });
+    writer.end('', 'utf-8', complete);
   };
 
   return app;

lib/appenders/file.js

@@ -20,6 +20,9 @@ function openTheStream(file, fileSize, numFiles, options) {
     numFiles,
     options
   );
+  stream.on('error', (err) => {
+    console.error('log4js.fileAppender - Writing to file %s, error happened ', file, err); //eslint-disable-line
+  });
   stream.on('drain', () => {
     process.emit("log4js:pause", false);
   });
@@ -55,25 +58,19 @@ function fileAppender(file, layout, logSize, numBackups, options, timezoneOffset
     timezoneOffset, ')'
   );
 
-  let alive = true;
-
   let writer = openTheStream(file, logSize, numBackups, options);
-  writer.on('error', (err) => {
-    alive = false;
-    console.error('log4js.fileAppender - Writing to file %s, error happened ', file, err); //eslint-disable-line
-  });
 
   const app = function (loggingEvent) {
-    if (!alive) {
+    if (!writer.writable) {
       return;
     }
     if (options.removeColor === true) {
       // eslint-disable-next-line no-control-regex
       const regex = /\x1b[[0-9;]*m/g;
       loggingEvent.data = loggingEvent.data.map(d => {
-        if (typeof d === 'string') return d.replace(regex, '')
-        return d
-      })
+        if (typeof d === 'string') return d.replace(regex, '');
+        return d;
+      });
     }
     if (!writer.write(layout(loggingEvent, timezoneOffset) + eol, "utf8")) {
       process.emit('log4js:pause', true);