refactor(@ngtools/logger): support strict null checks

Author: clydin

packages/@ngtools/logger/src/console-logger-stack.ts

@@ -1,30 +1,48 @@
 import {Logger} from './logger';
 
-let globalConsoleStack: Logger[] = null;
-let originalConsoleDebug: (message?: any, ...optionalParams: any[]) => void;
-let originalConsoleLog: (message?: any, ...optionalParams: any[]) => void;
-let originalConsoleWarn: (message?: any, ...optionalParams: any[]) => void;
-let originalConsoleError: (message?: any, ...optionalParams: any[]) => void;
+type ConsoleWriter = (message?: any, ...optionalParams: any[]) => void;
 
+let globalConsoleStack: Logger[] | null = null;
+let originalConsoleDebug: ConsoleWriter;
+let originalConsoleLog: ConsoleWriter;
+let originalConsoleWarn: ConsoleWriter;
+let originalConsoleError: ConsoleWriter;
+
+
+function _push(logger: Logger): Logger {
+  if (!globalConsoleStack) {
+    throw new Error('ConsoleLoggerStack must be started before pushing a logger.');
+  }
 
-function _push(logger: Logger) {
   if (globalConsoleStack.length == 0) {
     originalConsoleDebug = (console as any).debug;  // Some environment (node) don't have debug.
     originalConsoleLog = console.log;
     originalConsoleWarn = console.warn;
     originalConsoleError = console.error;
 
     (console as any).debug = (msg: string, ...args: any[]) => {
-      globalConsoleStack[globalConsoleStack.length - 1].debug(msg, { args });
+      const logger = ConsoleLoggerStack.top();
+      if (logger) {
+        logger.debug(msg, { args });
+      }
     };
     console.log = (msg: string, ...args: any[]) => {
-      globalConsoleStack[globalConsoleStack.length - 1].info(msg, { args });
+      const logger = ConsoleLoggerStack.top();
+      if (logger) {
+        logger.info(msg, { args });
+      }
     };
     console.warn = (msg: string, ...args: any[]) => {
-      globalConsoleStack[globalConsoleStack.length - 1].warn(msg, { args });
+      const logger = ConsoleLoggerStack.top();
+      if (logger) {
+        logger.warn(msg, { args });
+      }
     };
     console.error = (msg: string, ...args: any[]) => {
-      globalConsoleStack[globalConsoleStack.length - 1].error(msg, { args });
+      const logger = ConsoleLoggerStack.top();
+      if (logger) {
+        logger.error(msg, { args });
+      }
     };
   }
   globalConsoleStack.push(logger);
@@ -33,6 +51,9 @@ function _push(logger: Logger) {
 }
 
 function _pop() {
+  if (!globalConsoleStack) {
+    return;
+  }
   globalConsoleStack[globalConsoleStack.length - 1].complete();
   globalConsoleStack.pop();
   if (globalConsoleStack.length == 0) {
@@ -55,18 +76,16 @@ export class ConsoleLoggerStack {
   static push(logger: Logger): Logger;
   static push<T extends Logger>(loggerClass: LoggerConstructor<T>, ...args: any[]): Logger;
   static push<T extends Logger>(nameOrLogger: string | Logger | LoggerConstructor<T> = '',
-                                ...args: any[]) {
+                                ...args: any[]): Logger {
     if (typeof nameOrLogger == 'string') {
-      return _push(new Logger(nameOrLogger as string, this.top()));
+      return _push(new Logger(nameOrLogger, this.top()));
     } else if (nameOrLogger instanceof Logger) {
-      const logger = nameOrLogger as Logger;
-      if (logger.parent !== this.top()) {
+      if (nameOrLogger.parent !== this.top()) {
         throw new Error('Pushing a logger that is not a direct child of the top of the stack.');
       }
-      return _push(logger);
+      return _push(nameOrLogger);
     } else {
-      const klass = nameOrLogger as LoggerConstructor<T>;
-      return _push(new klass(...args, this.top()));
+      return _push(new nameOrLogger(...args, this.top()));
     }
   }
   static pop(): Logger | null {
@@ -82,19 +101,18 @@ export class ConsoleLoggerStack {
   static start(logger: Logger): Logger;
   static start<T extends Logger>(loggerClass: LoggerConstructor<T>, ...args: any[]): Logger;
   static start<T extends Logger>(nameOrLogger: string | Logger | LoggerConstructor<T> = '',
-                                ...args: any[]) {
+                                ...args: any[]): Logger {
     if (globalConsoleStack !== null) {
       throw new Error('Cannot start a new console logger stack while one is already going.');
     }
 
     globalConsoleStack = [];
     if (typeof nameOrLogger == 'string') {
-      return _push(new Logger(nameOrLogger as string, this.top()));
+      return _push(new Logger(nameOrLogger, this.top()));
     } else if (nameOrLogger instanceof Logger) {
-      return _push(nameOrLogger as Logger);
+      return _push(nameOrLogger);
     } else {
-      const klass = nameOrLogger as LoggerConstructor<T>;
-      return _push(new klass(...args, this.top()));
+      return _push(new nameOrLogger(...args, this.top()));
     }
   }
   static end() {

packages/@ngtools/logger/src/logger.spec.ts

@@ -38,7 +38,7 @@ describe('Logger', () => {
       .then(() => done(), (err: any) => done.fail(err));
 
     const childLogger = new Logger('child', logger);
-    childLogger.subscribe(null, null, () => hasCompleted = true);
+    childLogger.subscribe(undefined, undefined, () => hasCompleted = true);
     childLogger.debug('hello');
     childLogger.info('world');
     logger.complete();

packages/@ngtools/logger/src/logger.ts

@@ -29,7 +29,7 @@ export class Logger extends Observable<LogEntry> {
   protected _metadata: LoggerMetadata;
 
   private _obs: Observable<LogEntry>;
-  private _subscription: Subscription;
+  private _subscription: Subscription | null;
 
   protected get _observable() { return this._obs; }
   protected set _observable(v: Observable<LogEntry>) {
@@ -39,11 +39,17 @@ export class Logger extends Observable<LogEntry> {
     this._obs = v;
     if (this.parent) {
       this._subscription = this.subscribe((value: LogEntry) => {
-        this.parent._subject.next(value);
+        if (this.parent) {
+          this.parent._subject.next(value);
+        }
       }, (error: any) => {
-        this.parent._subject.error(error);
+        if (this.parent) {
+          this.parent._subject.error(error);
+        }
       }, () => {
-        this._subscription.unsubscribe();
+        if (this._subscription) {
+          this._subscription.unsubscribe();
+        }
         this._subscription = null;
       });
     }
@@ -60,9 +66,9 @@ export class Logger extends Observable<LogEntry> {
     }
     this._metadata = { name, path };
     this._observable = this._subject.asObservable();
-    if (parent) {
+    if (this.parent) {
       // When the parent completes, complete us as well.
-      this.parent._subject.subscribe(null, null, () => this.complete());
+      this.parent._subject.subscribe(undefined, undefined, () => this.complete());
     }
   }