diff --git a/.circleci/config.yml b/.circleci/config.yml
index 67d9fbe153..65dc3d2920 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -41,7 +41,7 @@ jobs:
       - restore_cache:
           key: angular-{{ .Branch }}-{{ checksum "npm-shrinkwrap.json" }}
 
-      - run: bazel run @io_bazel_rules_typescript_node//:bin/npm install
+      - run: bazel run @build_bazel_rules_typescript_node//:bin/npm install
       - run: bazel build ...
       - save_cache:
           key: angular-{{ .Branch }}-{{ checksum "npm-shrinkwrap.json" }}
diff --git a/packages/compiler-cli/src/compiler_host.ts b/packages/compiler-cli/src/compiler_host.ts
index 03424e9ebc..04d5083770 100644
--- a/packages/compiler-cli/src/compiler_host.ts
+++ b/packages/compiler-cli/src/compiler_host.ts
@@ -41,8 +41,8 @@ export class CompilerHost implements AotCompilerHost {
       protected program: ts.Program, protected options: AngularCompilerOptions,
       protected context: CompilerHostContext, collectorOptions?: CollectorOptions) {
     // normalize the path so that it never ends with '/'.
-    this.basePath = path.normalize(path.join(this.options.basePath, '.')).replace(/\\/g, '/');
-    this.genDir = path.normalize(path.join(this.options.genDir, '.')).replace(/\\/g, '/');
+    this.basePath = path.normalize(path.join(this.options.basePath !, '.')).replace(/\\/g, '/');
+    this.genDir = path.normalize(path.join(this.options.genDir !, '.')).replace(/\\/g, '/');
 
     const genPath: string = path.relative(this.basePath, this.genDir);
     this.isGenDirChildOfRootDir = genPath === '' || !genPath.startsWith('..');
@@ -312,7 +312,7 @@ export class CompilerHost implements AotCompilerHost {
       relativePath = relativePath.substr(3);
     }
 
-    return path.join(this.options.genDir, relativePath);
+    return path.join(this.options.genDir !, relativePath);
   }
 
   private hasBundleIndex(filePath: string): boolean {
diff --git a/packages/compiler-cli/src/extractor.ts b/packages/compiler-cli/src/extractor.ts
index 99a6e8f9f7..e87a370d76 100644
--- a/packages/compiler-cli/src/extractor.ts
+++ b/packages/compiler-cli/src/extractor.ts
@@ -36,7 +36,7 @@ export class Extractor {
     return promiseBundle.then(bundle => {
       const content = this.serialize(bundle, formatName);
       const dstFile = outFile || `messages.${ext}`;
-      const dstPath = path.join(this.options.genDir, dstFile);
+      const dstPath = path.join(this.options.genDir !, dstFile);
       this.host.writeFile(dstPath, content, false);
       return [dstPath];
     });
diff --git a/packages/compiler-cli/src/transformers/module_filename_resolver.ts b/packages/compiler-cli/src/transformers/module_filename_resolver.ts
index 5cf3012e2b..ba4ebd1971 100644
--- a/packages/compiler-cli/src/transformers/module_filename_resolver.ts
+++ b/packages/compiler-cli/src/transformers/module_filename_resolver.ts
@@ -27,8 +27,8 @@ class SingleRootDirModuleFilenameResolver implements ModuleFilenameResolver {
 
   constructor(private host: ModuleFilenameResolutionHost, private options: CompilerOptions) {
     // normalize the path so that it never ends with '/'.
-    this.basePath = path.normalize(path.join(options.basePath, '.')).replace(/\\/g, '/');
-    this.genDir = path.normalize(path.join(options.genDir, '.')).replace(/\\/g, '/');
+    this.basePath = path.normalize(path.join(options.basePath !, '.')).replace(/\\/g, '/');
+    this.genDir = path.normalize(path.join(options.genDir !, '.')).replace(/\\/g, '/');
 
     const genPath: string = path.relative(this.basePath, this.genDir);
     this.isGenDirChildOfRootDir = genPath === '' || !genPath.startsWith('..');
@@ -153,7 +153,7 @@ class MultipleRootDirModuleFilenameResolver implements ModuleFilenameResolver {
 
   constructor(private host: ModuleFilenameResolutionHost, private options: CompilerOptions) {
     // normalize the path so that it never ends with '/'.
-    this.basePath = path.normalize(path.join(options.basePath, '.')).replace(/\\/g, '/');
+    this.basePath = path.normalize(path.join(options.basePath !, '.')).replace(/\\/g, '/');
   }
 
   getNgCanonicalFileName(fileName: string): string {
@@ -282,4 +282,4 @@ function createModuleFilenameResolverHost(host: ts.ModuleResolutionHost):
   resolveModuleNameHost.realpath = (fileName: string) => fileName;
 
   return resolveModuleNameHost;
-}
\ No newline at end of file
+}