address CR feedback: use typeof check instead of checking undefined and null value

zhengbli · zhengbli · commit c244306514a7 · 2016-01-15T16:55:25.000-08:00
diff --git a/src/compiler/sys.ts b/src/compiler/sys.ts
@@ -376,13 +376,11 @@ namespace ts {
                 /**
                  * @param watcherPath is the path from which the watcher is triggered.
                  */
-                function fileEventHandler(eventName: string, relativefileName: string, baseDirPath: Path) {
+                function fileEventHandler(eventName: string, relativeFileName: string, baseDirPath: Path) {
                     // When files are deleted from disk, the triggered "rename" event would have a relativefileName of "undefined"
-                    /* tslint:disable:no-null */
-                    const filePath = relativefileName === undefined || relativefileName === null
+                    const filePath = typeof relativeFileName !== "string"
                         ? undefined
-                        : toPath(relativefileName, baseDirPath, createGetCanonicalFileName(sys.useCaseSensitiveFileNames));
-                    /* tslint:enable:no-null */
+                        : toPath(relativeFileName, baseDirPath, createGetCanonicalFileName(sys.useCaseSensitiveFileNames));
                     if (eventName === "change" && fileWatcherCallbacks.contains(filePath)) {
                         for (const fileCallback of fileWatcherCallbacks.get(filePath)) {
                             fileCallback(filePath);
