在生产模式下构建角度应用程序时出错

Question

当我想用prod标志构建我的应用程序时，由于在我的一个服务中使用Http模块，构建过程将失败。它无法解析此服务的参数。

这是代码示例

import { BadInput } from './../common/bad-input';
import { NotFoundError } from './../common/not-found-error';
import { AppError } from './../common/app-error';
import { Http } from '@angular/http';
import { Injectable } from '@angular/core';
import { Observable } from 'rxjs/Observable';
import 'rxjs/add/operator/catch';
import 'rxjs/add/operator/map';
import 'rxjs/add/observable/throw';

@Injectable()
export class DataService {
  constructor(private endpoint: string, private http: Http) { }

  private serverUrl:string ='http://example.com/api/'
  private url=this.serverUrl+this.endpoint;

  getAll() {
    return this.http.get(this.url)
      .map(response => response.json())
      .catch(this.handleError);
  }
private handleError(error: Response) {
    if (error.status === 400)
      return Observable.throw(new BadInput(error.json()));

    if (error.status === 404)
      return Observable.throw(new NotFoundError());

    return Observable.throw(new AppError(error))
  }
}

这是我使用ng build --prod时遇到的错误

ERROR in Error: Can't resolve all parameters for DataService in D:/src/app/services/data.service.ts: (?, [object Object]).
    at syntaxError (D:\node_modules\@angular\compiler\bundles\compiler.umd.js:1729:34)
    at CompileMetadataResolver._getDependenciesMetadata (D:\node_modules\@angular\compiler\bundles\compiler.umd.js:15965:35)
    at CompileMetadataResolver._getTypeMetadata (D:\node_modules\@angular\compiler\bundles\compiler.umd.js:15833:26)
    at CompileMetadataResolver._getInjectableMetadata (D:\node_modules\@angular\compiler\bundles\compiler.umd.js:15819:21)
    at CompileMetadataResolver.getProviderMetadata (D:\node_modules\@angular\compiler\bundles\compiler.umd.js:16110:40)
    at D:\node_modules\@angular\compiler\bundles\compiler.umd.js:16039:49
    at Array.forEach (<anonymous>)
    at CompileMetadataResolver._getProvidersMetadata (D:\node_modules\@angular\compiler\bundles\compiler.umd.js:15999:19)
    at CompileMetadataResolver.getNgModuleMetadata (D:\node_modules\@angular\compiler\bundles\compiler.umd.js:15654:50)
    at addNgModule (D:\node_modules\@angular\compiler\bundles\compiler.umd.js:24408:58)
    at D:\node_modules\@angular\compiler\bundles\compiler.umd.js:24419:14
    at Array.forEach (<anonymous>)
    at _createNgModules (D:\node_modules\@angular\compiler\bundles\compiler.umd.js:24418:26)
    at analyzeNgModules (D:\node_modules\@angular\compiler\bundles\compiler.umd.js:24293:14)
    at analyzeAndValidateNgModules (D:\node_modules\@angular\compiler\bundles\compiler.umd.js:24303:35)
    at AotCompiler.analyzeModulesAsync (D:\node_modules\@angular\compiler\bundles\compiler.umd.js:23937:46)

Answer 1

Http已被弃用，支持HttpClient，所以你可能想看看这个：http://brianflove.com/2017/07/21/migrating-to-http-client/

与此同时，我还没有尝试过这个，但如果你没有使用AOT选项，你可能会继续使用Http一段时间，这个选项默认为prod版本打开。尝试一下：

ng build --prod --aot=false