Typescript 定义全局常量
在Angular 1.x中,可以定义如下常量:Typescript 定义全局常量,typescript,angular,Typescript,Angular,在Angular 1.x中,可以定义如下常量: export class CONSTANT { public static message2 = [ { "NAME_REQUIRED": "Name is required" } ] public static message = { "NAME_REQUIRED": "Name is required", } } import { Component, OnInit
export class CONSTANT {
public static message2 = [
{ "NAME_REQUIRED": "Name is required" }
]
public static message = {
"NAME_REQUIRED": "Name is required",
}
}
import { Component, OnInit } from '@angular/core';
import { CONSTANT } from '../../constants/dash-constant';
@Component({
selector : 'team-component',
templateUrl: `../app/modules/dashboard/dashComponents/teamComponents/team.component.html`,
})
export class TeamComponent implements OnInit {
constructor() {
console.log(CONSTANT.message2[0].NAME_REQUIRED);
console.log(CONSTANT.message.NAME_REQUIRED);
}
ngOnInit() {
console.log("oninit");
console.log(CONSTANT.message2[0].NAME_REQUIRED);
console.log(CONSTANT.message.NAME_REQUIRED);
}
}
angular.module('mainApp.config',[])
.constant('API_端点','http://127.0.0.1:6666/api/')
在Angular(带TypeScript)中,什么是等效的
我只是不想在我的所有服务中一遍又一遍地重复API基本url。只需使用一个Typescript常量即可
export var API_ENDPOINT = 'http://127.0.0.1:6666/api/';
您可以在依赖项注入器中使用
bootstrap(AppComponent, [provide(API_ENDPOINT, {useValue: 'http://127.0.0.1:6666/api/'}), ...]);
在Angular2中,您有以下定义,允许您设置不同类型的依赖项:
provide(token: any, {useClass, useValue, useExisting, useFactory, deps, multi}
与角度1相比
Angular1中的app.service
相当于Angular2中的useClass
Angular1中的app.factory
相当于Angular2中的useFactory
app.constant
和app.value
已简化为useValue
,约束更少。i、 e.不再有config
块
app.provider
-Angular 2中没有等价物
示例
const API_URL = process.env.API_URL = 'http://localhost:3000/';
const JWT_TOKEN_NAME = "id_token";
...
plugins: [
// NOTE: when adding more properties, make sure you include them in custom-typings.d.ts
new DefinePlugin({
'API_URL': JSON.stringify(API_URL),
'JWT_TOKEN_NAME': JSON.stringify(JWT_TOKEN_NAME)
}),
declare var API_URL: string;
declare var JWT_TOKEN_NAME: string;
interface GlobalEnvironment {
API_URL: string;
JWT_TOKEN_NAME: string;
}
'use strict';
export const dist = '../path/to/dist/';
import * as AppConst from '../app.const';
@Injectable()
export class AppService {
constructor (
) {
console.log('dist path', AppConst.dist );
}
}
要使用根部喷射器进行设置,请执行以下操作:
bootstrap(AppComponent,[provide(API_ENDPOINT, { useValue='http://127.0.0.1:6666/api/' })]);
providers: [provide(API_ENDPOINT, { useValue: 'http://127.0.0.1:6666/api/'})]
或使用部件的喷油器进行设置:
bootstrap(AppComponent,[provide(API_ENDPOINT, { useValue='http://127.0.0.1:6666/api/' })]);
providers: [provide(API_ENDPOINT, { useValue: 'http://127.0.0.1:6666/api/'})]
provide
是以下内容的缩写:
var injectorValue = Injector.resolveAndCreate([
new Provider(API_ENDPOINT, { useValue: 'http://127.0.0.1:6666/api/'})
]);
使用喷油器,很容易获得数值:
var endpoint = injectorValue.get(API_ENDPOINT);
以下更改适用于Angular 2最终版本:
export class AppSettings {
public static API_ENDPOINT='http://127.0.0.1:6666/api/';
}
import {Http} from 'angular2/http';
import {Message} from '../models/message';
import {Injectable} from 'angular2/core';
import {Observable} from 'rxjs/Observable';
import {AppSettings} from '../appSettings';
import 'rxjs/add/operator/map';
@Injectable()
export class MessageService {
constructor(private http: Http) { }
getMessages(): Observable<Message[]> {
return this.http.get(AppSettings.API_ENDPOINT+'/messages')
.map(response => response.json())
.map((messages: Object[]) => {
return messages.map(message => this.parseData(message));
});
}
private parseData(data): Message {
return new Message(data);
}
}
然后在服务中:
export class AppSettings {
public static API_ENDPOINT='http://127.0.0.1:6666/api/';
}
import {Http} from 'angular2/http';
import {Message} from '../models/message';
import {Injectable} from 'angular2/core';
import {Observable} from 'rxjs/Observable';
import {AppSettings} from '../appSettings';
import 'rxjs/add/operator/map';
@Injectable()
export class MessageService {
constructor(private http: Http) { }
getMessages(): Observable<Message[]> {
return this.http.get(AppSettings.API_ENDPOINT+'/messages')
.map(response => response.json())
.map((messages: Object[]) => {
return messages.map(message => this.parseData(message));
});
}
private parseData(data): Message {
return new Message(data);
}
}
从'angular2/Http'导入{Http};
从“../models/Message”导入{Message};
从'angular2/core'导入{Injectable};
从“rxjs/Observable”导入{Observable};
从“../AppSettings”导入{AppSettings};
导入'rxjs/add/operator/map';
@可注射()
导出类消息服务{
构造函数(私有http:http){}
getMessages():可观察{
返回此.http.get(AppSettings.API_ENDPOINT+/messages)
.map(response=>response.json())
.map((消息:Object[])=>{
returnmessages.map(message=>this.parseData(message));
});
}
私有数据(data):消息{
返回新消息(数据);
}
}
虽然将带有字符串常量的AppSettings类作为ApiEndpoint的方法可行,但这并不理想,因为在单元测试时,我们无法将这个真实的ApiEndpoint替换为其他一些值
我们需要能够将这个api端点注入到我们的服务中(考虑将一个服务注入到另一个服务中)。我们也不需要为此创建一个完整的类,我们所要做的就是将一个字符串注入作为我们的端点的服务中。要完成,以下是有关如何在Angular 2中完成的完整代码:
首先,我们需要告诉Angular,当我们在应用程序中请求ApiEndpoint时,如何提供ApiEndpoint的实例(将其视为注册依赖项):
然后在服务中,我们将该ApiEndpoint注入到服务构造函数中,Angular将根据上述注册为我们提供:
import {Http} from 'angular2/http';
import {Message} from '../models/message';
import {Injectable, Inject} from 'angular2/core'; // * We import Inject here
import {Observable} from 'rxjs/Observable';
import {AppSettings} from '../appSettings';
import 'rxjs/add/operator/map';
@Injectable()
export class MessageService {
constructor(private http: Http,
@Inject('ApiEndpoint') private apiEndpoint: string) { }
getMessages(): Observable<Message[]> {
return this.http.get(`${this.apiEndpoint}/messages`)
.map(response => response.json())
.map((messages: Object[]) => {
return messages.map(message => this.parseData(message));
});
}
// the rest of the code...
}
从'angular2/Http'导入{Http};
从“../models/Message”导入{Message};
从“angular2/core”导入{Injectable,injecte};//*我们在这里进口
从“rxjs/Observable”导入{Observable};
从“../AppSettings”导入{AppSettings};
导入'rxjs/add/operator/map';
@可注射()
导出类消息服务{
构造函数(私有http:http,
@注入('apidentpoint')私有apidentpoint:string){}
getMessages():可观察{
返回this.http.get(`${this.apidendpoint}/messages`)
.map(response=>response.json())
.map((消息:Object[])=>{
returnmessages.map(message=>this.parseData(message));
});
}
//代码的其余部分。。。
}
使用生成过程中生成的属性文件既简单又容易。这是Angular CLI使用的方法。为每个环境定义属性文件,并在生成过程中使用命令确定将哪个文件复制到应用程序。然后只需导入要使用的属性文件
已为角度4更新+
现在,我们可以简单地使用environments文件,如果您的项目是通过angular cli生成的,angular将提供默认文件
比如说
在您的环境文件夹中创建以下文件
environment.prod.ts
environment.qa.ts
environment.dev.ts
environment.prod.ts
export const environment = { production: true, apiHost: 'https://api.somedomain.com/prod/v1/', CONSUMER_KEY: 'someReallyStupidTextWhichWeHumansCantRead', codes: [ 'AB', 'AC', 'XYZ' ], };
export const environment = { production: false, apiHost: 'https://api.somedomain.com/qa/v1/', CONSUMER_KEY : 'someReallyStupidTextWhichWeHumansCantRead', codes: [ 'AB', 'AC', 'XYZ' ], };
export const environment = { production: false, apiHost: 'https://api.somedomain.com/dev/v1/', CONSUMER_KEY : 'someReallyStupidTextWhichWeHumansCantRead', codes: [ 'AB', 'AC', 'XYZ' ], };
environment.qa.ts
export const environment = { production: true, apiHost: 'https://api.somedomain.com/prod/v1/', CONSUMER_KEY: 'someReallyStupidTextWhichWeHumansCantRead', codes: [ 'AB', 'AC', 'XYZ' ], };
export const environment = { production: false, apiHost: 'https://api.somedomain.com/qa/v1/', CONSUMER_KEY : 'someReallyStupidTextWhichWeHumansCantRead', codes: [ 'AB', 'AC', 'XYZ' ], };
export const environment = { production: false, apiHost: 'https://api.somedomain.com/dev/v1/', CONSUMER_KEY : 'someReallyStupidTextWhichWeHumansCantRead', codes: [ 'AB', 'AC', 'XYZ' ], };
environment.dev.ts
export const environment = { production: true, apiHost: 'https://api.somedomain.com/prod/v1/', CONSUMER_KEY: 'someReallyStupidTextWhichWeHumansCantRead', codes: [ 'AB', 'AC', 'XYZ' ], };
export const environment = { production: false, apiHost: 'https://api.somedomain.com/qa/v1/', CONSUMER_KEY : 'someReallyStupidTextWhichWeHumansCantRead', codes: [ 'AB', 'AC', 'XYZ' ], };
export const environment = { production: false, apiHost: 'https://api.somedomain.com/dev/v1/', CONSUMER_KEY : 'someReallyStupidTextWhichWeHumansCantRead', codes: [ 'AB', 'AC', 'XYZ' ], };
clientUtilServices.ts
从“../../environments/environment”导入{environment}代码>
getHostURL(): string {
return environment.apiHost;
}
构建中的用例
打开angular cli文件.angular cli.json
并在中的“应用程序”:[{…}]
添加以下代码
"apps":[{
"environments": {
"dev": "environments/environment.ts",
"prod": "environments/environment.prod.ts",
"qa": "environments/environment.qa.ts",
}
}
]
如果要为生产构建,请运行ng build--env=prod
,它将从environment.prod.ts
读取配置,与您为qa
或dev
执行此操作的方式相同
##老答案
在我的提供商中,我一直在做如下工作:
import {Injectable} from '@angular/core';
@Injectable()
export class ConstantService {
API_ENDPOINT :String;
CONSUMER_KEY : String;
constructor() {
this.API_ENDPOINT = 'https://api.somedomain.com/v1/';
this.CONSUMER_KEY = 'someReallyStupidTextWhichWeHumansCantRead'
}
}
然后我可以在任何地方访问所有常量数据
import {Injectable} from '@angular/core';
import {Http} from '@angular/http';
import 'rxjs/add/operator/map';
import {ConstantService} from './constant-service'; //This is my Constant Service
@Injectable()
export class ImagesService {
constructor(public http: Http, public ConstantService: ConstantService) {
console.log('Hello ImagesService Provider');
}
callSomeService() {
console.log("API_ENDPOINT: ",this.ConstantService.API_ENDPOINT);
console.log("CONSUMER_KEY: ",this.ConstantService.CONSUMER_KEY);
var url = this.ConstantService.API_ENDPOINT;
return this.http.get(url)
}
}
可以找到angular团队自己提供的配置解决方案
以下是所有相关代码:
1) app.config.ts
import { OpaqueToken } from "@angular/core";
export let APP_CONFIG = new OpaqueToken("app.config");
export interface IAppConfig {
apiEndpoint: string;
}
export const AppConfig: IAppConfig = {
apiEndpoint: "http://localhost:15422/api/"
};
2) app.module.ts
import { APP_CONFIG, AppConfig } from './app.config';
@NgModule({
providers: [
{ provide: APP_CONFIG, useValue: AppConfig }
]
})
3) 你的服务
import { APP_CONFIG, IAppConfig } from './app.config';
@Injectable()
export class YourService {
constructor(@Inject(APP_CONFIG) private config: IAppConfig) {
// You can use config.apiEndpoint now
}
}
现在,您可以在任何地方插入配置,而无需使用字符串名称,也无需使用接口进行静态检查
当然,您可以进一步分离接口和常量,以便能够在生产和开发中提供不同的值,例如,如果您正在使用,我建议您可以为不同的环境设置常量。当你有不同的常数时,这是特别有价值的
export const environment = {
production: false,
apiUrl: 'http://localhost:8000/api/'
};
import { environment } from '../../environments/environment';
...
environment.apiUrl;
const api_endpoint = 'http://127.0.0.1:6666/api/';
@NgModule({
declarations: [AppComponent],
bootstrap: [AppComponent],
providers: [
MessageService,
{provide: 'API_ENDPOINT', useValue: api_endpoint}
]
})
export class AppModule {
}
import {Injectable, Inject} from '@angular/core';
@Injectable()
export class MessageService {
constructor(private http: Http,
@Inject('API_ENDPOINT') private api_endpoint: string) { }
getMessages(): Observable<Message[]> {
return this.http.get(this.api_endpoint+'/messages')
.map(response => response.json())
.map((messages: Object[]) => {
return messages.map(message => this.parseData(message));
});
}
private parseData(data): Message {
return new Message(data);
}
}
export class SettingService {
constructor(private http: HttpClient) {
}
public getJSON(file): Observable<any> {
return this.http.get("./assets/configs/" + file + ".json");
}
public getSetting(){
// use setting here
}
}
{
"baseUrl": "http://localhost:52555"
}
{
provide: APP_INITIALIZER,
useFactory: (setting: SettingService) => function() {return setting.getSetting()},
deps: [SettingService],
multi: true
}
// environments\ienvironments.ts
export class IEnvironment implements IEnvironmentParams {
public production: boolean;
public basicURL: string = 'https://www.someawesomedomain.com';
public siteName: string = 'My awesome site';
constructor(params: IEnvironmentParams) {
this.production = params.production ?? false;
this.basicURL = params.basicURL ?? this.basicURL;
this.siteName = params.siteName ?? this.siteName;
}
}
export interface IEnvironmentParams {
production: boolean;
basicURL?: string;
siteName?: string;
}
// environments\environment.prod.ts
import {IEnvironment, IEnvironmentParams} from "./ienvironment";
const params: IEnvironmentParams = {
production: true
};
export const environment: IEnvironment = new IEnvironment(params);
// environments\environment.ts
import {IEnvironment, IEnvironmentParams} from "./ienvironment";
const params: IEnvironmentParams = {
production: false
};
export const environment: IEnvironment = new IEnvironment(params);
import {environment} from "../environments/environment";
// app-routing.module.ts
const routes: Routes = [
{
path: '', component: HomeComponent,
data: {
title: `${environment.siteName} | Home page title!`,
description: 'some page description',
}
}
];
// home.component.ts
@Component({
selector: 'app-home',
templateUrl: './home.component.html',
styleUrls: ['./home.component.scss']
})
export class HomeComponent {
constructor() {
console.log(`home component constructor - showing evironment.siteName - ${environment.siteName}`);
}
}