我使用此链接将我的简单角度前端升级到Angular 7：
在更新时，我收到关于package.json和polyfills.ts文件的一些警告：
UPDATE package.json (1313 bytes)
npm WARN @ngtools/webpack@6.1.5 requires a peer of typescript@~2.4.0 || ~2.5.0 || ~2.6.0 || ~2.7.0 || ~2.8.0 || ~2.9.0 but none is installed. You must install peer dependencies yourself.
npm WARN codelyzer@4.2.1 requires a peer of @angular/compiler@>=2.3.1 <7.0.0 || >6.0.0-beta <7.0.0 but none is installed. You must install peer dependencies yourself.
npm WARN codelyzer@4.2.1 requires a peer of @angular/core@>=2.3.1 <7.0.0 || >6.0.0-beta <7.0.0 but none is installed. You must install peer dependencies yourself.
npm WARN codelyzer@4.2.1 requires a peer of @angular/platform-browser-dynamic@>=2.3.1 <7.0.0 || >6.0.0-beta <7.0.0 but none is installed. You must install peer dependencies yourself.
npm WARN codelyzer@4.2.1 requires a peer of @angular/platform-browser@>=2.3.1 <7.0.0 || >6.0.0-beta <7.0.0 but none is installed. You must install peer dependencies yourself.
npm WARN codelyzer@4.2.1 requires a peer of @angular/common@>=2.3.1 <7.0.0 || >6.0.0-beta <7.0.0 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"})
added 69 packages, removed 4 packages, updated 16 packages and moved 2 packages in 43.395s
UPDATE package.json (1315 bytes)
UPDATE src/polyfills.ts (3165 bytes)
npm WARN codelyzer@4.2.1 requires a peer of @angular/compiler@>=2.3.1 <7.0.0 || >6.0.0-beta <7.0.0 but none is installed. You must install peer dependencies yourself.
npm WARN codelyzer@4.2.1 requires a peer of @angular/core@>=2.3.1 <7.0.0 || >6.0.0-beta <7.0.0 but none is installed. You must install peer dependencies yourself.
npm WARN codelyzer@4.2.1 requires a peer of @angular/platform-browser-dynamic@>=2.3.1 <7.0.0 || >6.0.0-beta <7.0.0 but none is installed. You must install peer dependencies yourself.
npm WARN codelyzer@4.2.1 requires a peer of @angular/platform-browser@>=2.3.1 <7.0.0 || >6.0.0-beta <7.0.0 but none is installed. You must install peer dependencies yourself.
npm WARN codelyzer@4.2.1 requires a peer of @angular/common@>=2.3.1 <7.0.0 || >6.0.0-beta <7.0.0 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"})
我也有打字稿（3.0.1）中的错误：
Error:Initialization error (angular 2 language service). Cannot read property 'CommandTypes' of undefined
有人可以建议解决方法，以解决这些依赖关系警告和打字稿错误吗？ 我需要手动更改依赖项吗？如果是的话，我需要一个示例来说明...
答案 0 :(得分：1)
问题是您没有这两个软件包的最新版本。
Codelyzer更新到最新版本。 ng update --all应该可以这样做，否则您也可以手动编辑package.json。您会看到here已使该软件包的最新版本（4.5.0）与Angular 7兼容，因此您需要使用它而不是4.2.1版本。
@ngtools/webpack相同，您需要使用最新版本（请参见here，它是7.0.2）。可能您的packages.json中没有明确显示此代码，因此您可能只需要在运行npm cache clean -f之前执行ng update。如果仍然无法执行此操作，建议您删除node_modules目录，这将强制npm install从存储库中的最新版本重建所有文件，前提是您正确更新了{{1 }}（手动或通过package.json）。
答案 1 :(得分：0)
您是否删除了旧的import { Injectable } from '@angular/core';
import { HttpClient} from '@angular/common/http';
interface IuserData{
userId: number;
}
@Injectable({
providedIn: 'root'
})
export class HttpService {
constructor(private http: HttpClient) { }
getUserId(){
return this.http.get<IuserData>("https://jsonplaceholder.typicode.com/todos/1").subscribe(data => {
console.log('User ID: ' + data.userId)
})
}
}
文件夹？如果没有，请删除它，如果存在，请同时删除package-lock.json。清理npm缓存node_modules并尝试安装所有软件包