在Angular教程（英雄之旅）中遇到的困境我想说
在一直循着Angular官方教程进行学习时，不小心陷入了困境。
环境
-
- macOS Mojave(10.14.6)
-
- Docker
Angular CLI: 8.3.19
Node: 13.1.0
OS: linux x64
Angular: 8.2.14
卡在一处
教程 > 6.HTTP > 模拟数据服务器
所以，当我在此页面上输入以下命令时…
#npm install angular-in-memory-web-api --save
这个地方。在导入 RxJS 的时候发生了错误。
import { Observable, of } from 'rxjs';
为什么？
仔细一看，发现当执行 “npm install ~”时，出现了如下警告。
#install angular-in-memory-web-api --save
(中略)
npm notice created a lockfile as package-lock.json. You should commit this file.
npm WARN @angular/common@8.2.14 requires a peer of rxjs@^6.4.0 but none is installed. You must install peer dependencies yourself.
npm WARN @angular/core@8.2.14 requires a peer of rxjs@^6.4.0 but none is installed. You must install peer dependencies yourself.
npm WARN @angular/forms@8.2.14 requires a peer of rxjs@^6.4.0 but none is installed. You must install peer dependencies yourself.
npm WARN @angular/router@8.2.14 requires a peer of rxjs@^6.4.0 but none is installed. You must install peer dependencies yourself.
npm WARN angular-in-memory-web-api@0.9.0 requires a peer of rxjs@^6.0.0 but none is installed. You must install peer dependencies yourself.
npm WARN optional SKIPPING OPTIONAL DEPENDENCY: fsevents@1.2.9 (node_modules/fsevents):
npm WARN notsup SKIPPING OPTIONAL DEPENDENCY: Unsupported platform for fsevents@1.2.9: wanted {"os":"darwin","arch":"any"} (current: {"os":"linux","arch":"x64"})
+ angular-in-memory-web-api@0.9.0
added 88 packages from 33 contributors, removed 64 packages, updated 1044 packages and audited 20998 packages in 260.873s
found 0 vulnerabilities
版本依赖好像不一样。（大概吧）
策略来解决问题。
那么，我已经放进去这么多了。
# npm install -g npm /* npmのアップデート */
# npm install rxjs
# npm install tslib
关于 npm 命令的详细信息，请参考这里。
由于这样的原因，错误已经成功消失了。
版本变化 huà)
我使用以下的命令来查看，想知道实际版本发生了什么变化。
# ng version
之前
Package Version
-----------------------------------------------------------
@angular-devkit/architect 0.803.19
@angular-devkit/build-angular 0.803.19
@angular-devkit/build-optimizer 0.803.19
@angular-devkit/build-webpack 0.803.19
@angular-devkit/core 8.3.19
@angular-devkit/schematics 8.3.19
@angular/cli 8.3.19
@ngtools/webpack 8.3.19
@schematics/angular 8.3.19
@schematics/update 0.803.19
rxjs 6.4.0
typescript 3.5.3
webpack 4.39.2
结束了
Package Version
-----------------------------------------------------------
@angular-devkit/architect 0.803.19
@angular-devkit/build-angular 0.803.19
@angular-devkit/build-optimizer 0.803.19
@angular-devkit/build-webpack 0.803.19
@angular-devkit/core 8.3.19
@angular-devkit/schematics 8.3.19
@angular/cli 8.3.19
@ngtools/webpack 8.3.19
@schematics/angular 8.3.19
@schematics/update 0.803.19
rxjs 6.4.0
typescript 3.5.3
webpack 4.39.2
嗯？还没改变？！那么，那个错误是什么？！
…虽然我有点在意，但我还是继续进行一小段的教程吧！
