按照文檔開始使用步驟遇到錯誤無法繼續(xù)

使用ng add ng-alain添加模塊，遇到錯誤進行下一步學習，完整的輸出信息：

$ ng add ng-alain
Installing packages for tooling via npm.
npm WARN ng-alain@1.4.0 requires a peer of @angular-devkit/core@^0.6.1 but none is installed. You must install peer dependencies yourself.
npm WARN ng-alain@1.4.0 requires a peer of @angular-devkit/schematics@^0.6.1 but none is installed. You must install peer dependencies yourself.
npm WARN ng-alain@1.4.0 requires a peer of @schematics/angular@^0.6.1 but none is installed. You must install peer dependencies yourself.
npm WARN optional SKIPPING OPTIONAL DEPENDENCY: fsevents@1.2.4 (node_modules\fsevents):
npm WARN notsup SKIPPING OPTIONAL DEPENDENCY: Unsupported platform for fsevents@1.2.4: wanted {"os":"darwin","arch":"any"} (current: {"os":"win32","arch":"x64"})

+ ng-alain@1.4.0
updated 1 package in 17.296s
Installed packages for tooling via npm.
Cannot read property 'build' of undefined

接著運行教程中的下一行命令ng server就會報錯：

$ ng server
The specified command ("server") is invalid. For a list of available options,
run "ng help".
Did you mean "serve"?

angular版本信息：

Angular CLI: 6.2.1
Node: 8.11.2
OS: win32 x64
Angular: 6.1.7
... animations, common, compiler, compiler-cli, core, forms
... http, language-service, platform-browser
... platform-browser-dynamic, router

Package                           Version
-----------------------------------------------------------
@angular-devkit/architect         0.8.1
@angular-devkit/build-angular     0.8.1
@angular-devkit/build-optimizer   0.8.1
@angular-devkit/build-webpack     0.8.1
@angular-devkit/core              0.8.1
@angular-devkit/schematics        0.8.1
@angular/cli                      6.2.1
@ngtools/webpack                  6.2.1
@schematics/angular               0.8.1
@schematics/update                0.8.1
rxjs                              6.2.2
typescript                        2.9.2
webpack                           4.17.2

初次使用，不太懂怎么處理，還請同學們幫幫忙，十分感謝。