#137 reverse changelog

CHANGELOG.md

@@ -2,13 +2,11 @@
 
 
 
-<a name="v0.3.3"></a>
-## v0.3.3 (2017-02-05)
+<a name="v0.3.5"></a>
+## v0.3.5 (2017-02-05)
 
-*  #137 Fix changelog format and escaping ([c1b10ea](https://github.com/micmro/PerfCascade/commit/c1b10ea))
-* #137 automatic changelog creation added ([6ced761](https://github.com/micmro/PerfCascade/commit/6ced761))
-* #137 speed up release branch checkout ([522ba06](https://github.com/micmro/PerfCascade/commit/522ba06))
-* format fix ([39acd2f](https://github.com/micmro/PerfCascade/commit/39acd2f))
+* #137 ensure CHANGELOG.md is committed ([645e53f](https://github.com/micmro/PerfCascade/commit/645e53f))
+* append missing v0.3.4 changelog ([c794281](https://github.com/micmro/PerfCascade/commit/c794281))
 
 
 
@@ -20,11 +18,10 @@
 
 
 
-<a name="v0.3.5"></a>
-## v0.3.5 (2017-02-05)
-
-* #137 ensure CHANGELOG.md is committed ([645e53f](https://github.com/micmro/PerfCascade/commit/645e53f))
-* append missing v0.3.4 changelog ([c794281](https://github.com/micmro/PerfCascade/commit/c794281))
-
-
+<a name="v0.3.3"></a>
+## v0.3.3 (2017-02-05)
 
+* #137 Fix changelog format and escaping ([c1b10ea](https://github.com/micmro/PerfCascade/commit/c1b10ea))
+* #137 automatic changelog creation added ([6ced761](https://github.com/micmro/PerfCascade/commit/6ced761))
+* #137 speed up release branch checkout ([522ba06](https://github.com/micmro/PerfCascade/commit/522ba06))
+* format fix ([39acd2f](https://github.com/micmro/PerfCascade/commit/39acd2f))

build-utils/grunt-tasks/changelog-custom.js

@@ -12,6 +12,40 @@ const escapeForBash = (str) => {
     .replace(/'/g, '\'"\'"\''); //escape single quotes the ugly bash way
 };
 
+/**
+ * Writes a log to a file
+ * @param  {string} path  filename/path to write to
+ * @param  {string} newLog  new Changelog entry to add
+ * @param  {number} headerLineCount  Number of lines the header occupies
+ */
+function appendLogToFileStream(path, newLog, headerLineCount) {
+  let wStr = fs.createWriteStream(path)
+
+  fs.readFile(path, (err, data) => {
+    if (err) {
+      wStr.emit('error', err);
+      return;
+    }
+    /** existing changelog */
+    let oldChangelog = data.toString().split('\n');
+    /** lines used by the default header */
+    let logHeader = oldChangelog.slice(0, headerLineCount);
+    /** previous changelog entries */
+    let prevLogs = oldChangelog.slice(headerLineCount);
+
+    var s = new Readable;
+    s.pipe(wStr);
+    s.push(logHeader.join('\n') + '\n');    // the string you want
+    s.push(newLog);
+    s.push(prevLogs.join('\n'));
+    // s.push('c aaa bbbb cccc')    // the string you want
+    s.push(null);      // indicates end-of-file basically - the end of the stream)
+  });
+
+  return wStr;
+};
+
+
 /**
  * @param  {IGrunt} grunt - Grunt instance
  */
@@ -28,18 +62,16 @@ module.exports = function (grunt) {
     readDataStream
       .on('data', (chunk) => tmpBuffer += chunk)
       .on('end', () => {
-        let lines = tmpBuffer.split("\n");
+        const lines = tmpBuffer.split('\n');
         lines.shift(); //remove the html-ancor tag in the first line
         grunt.config.data.changelog = escapeForBash(lines.join('\n'));
-        readDataStream.end();
-      });
 
-    // changlog file writer
-    let appenFileStream = fs.createWriteStream(options.file, { 'flags': 'a' })
-      .on('error', grunt.log.error)
-      .on('close', () => {
-        grunt.log.ok(`${options.file} updated with latest changelog for ${options.version}`);
-        done();
+        appendLogToFileStream(options.file, lines.join('\n'), 5)
+          .on('error', grunt.log.error)
+          .on('close', () => {
+            grunt.log.ok(`${options.file} updated with latest changelog for ${options.version}`);
+            done();
+          });
       });
 
     // get changelog
@@ -50,6 +82,6 @@ module.exports = function (grunt) {
       }
     }, {
         version: options.version
-      }).pipe(readDataStream).pipe(appenFileStream); // or any writable stream
+      }).pipe(readDataStream); // or any writable stream
   });
 };