Angular 有人能解释lambda/fat-arrow角函数调用的语法和含义吗
有人能帮我解释一下语法和意思吗？我知道，Angular 有人能解释lambda/fat-arrow角函数调用的语法和含义吗,angular,Angular,有人能帮我解释一下语法和意思吗？我知道，put$具有返回可观察对象的含义，因此它在公司服务中调用put，它有两个参数，我知道subscribe是什么意思，但我需要一些帮助来理解它 如果你有一个链接到一个好的教程，这将是伟大的 this.companyService.put$(this.currentId, this.appMenu.currentObject) .subscribe(selectedCompany => {this.appMenu.cu
put$this.companyService.put$(this.currentId, this.appMenu.currentObject)
.subscribe(selectedCompany => {this.appMenu.currentObject = selectedCompany});
import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { Observable, BehaviorSubject } from 'rxjs';
import { Company } from '../models/company.model';
@Injectable({
providedIn: 'root'
})
export class CompanyService {
private url: string;
constructor(private http: HttpClient) {
this.url = "http://localhost:8080/niche/company";
}
getOne$ = (companyId: number): Observable<Company> => this.http.get<Company>(`${this.url}/${companyId}`);
get$ = (): Observable<Company[]> => this.http.get<Company[]>(this.url);
post$ = (company: Company): Observable<Company> => this.http.post<Company>(this.url, { company });
patch$ = (companyId: number, company: Company): Observable<Company> => this.http.patch<Company>(`${this.url}/${companyId}`, { company });
put$ = (companyId: number, company: Company): Observable<Company> => this.http.put<Company>(`${this.url}/${companyId}`, company );
delete$ = (companyId: number): Observable<Company> => this.http.delete<Company>(`${this.url}/${companyId}`);
}
从'@angular/core'导入{Injectable}；
从'@angular/common/http'导入{HttpClient}；
从“rxjs”导入{observeable，BehaviorSubject}；
从“../models/Company.model”导入{Company}；
@注射的({
providedIn:'根'
})
出口类公司服务{
私有url:string；
构造函数（专用http:HttpClient）{
this.url=”http://localhost:8080/niche/company";
}
getOne$=（companyId:number）：Observable=>this.http.get（`${this.url}/${companyId}`）；
get$=（）：Observable=>this.http.get（this.url）；
post$=（company:company）：可观察=>this.http.post（this.url，{company}）；
补丁$=（companyId:number，company:company）：可观察=>this.http.patch（`${this.url}/${companyId}'，{company}）；
put$=（companyId:number，company:company）：可观察=>this.http.put（`${this.url}/${companyId}，company）；
delete$=（companyId:number）：Observable=>this.http.delete（`${this.url}/${companyId}`）；
}
this.companyService
.put$(this.currentId, this.appMenu.currentObject)
.subscribe(selectedCompany => {
this.appMenu.currentObject = selectedCompany
});
数据库客户端应用程序，在您的应用程序中是Angular应用程序this.companyService.putthis.currentId，this.appMenu.currentObject.subscribe// 1. Here we are creating a new XMLHttpRequest object
let xhr = new XMLHttpRequest();
// 2. Then we set its configuration: request of GET type for the URL /somePage/anotherPage
xhr.open('GET', '/somePage/anotherPage');
// 3. We are sending the request over the network
xhr.send();
// 4. Then this rows will be called after the response is received from the
// server to the client
xhr.onload = function () {
if (xhr.status != 200) { // see what HTTP status of the response is come
alert(`Error ${xhr.status}: ${xhr.statusText}`); // e.g. 404: Not Found
} else { // show the result
alert(`Great, got ${xhr.response.length} bytes`); // responseText is the server
}
};
// Get progress from XMLHttpRequest
xhr.onprogress = function (event) {
if (event.lengthComputable) {
alert(`We are received ${event.loaded} of ${event.total} bytes`);
} else {
alert(`We are received ${event.loaded} bytes`); // no Content-Length
}
};
xhr.onerror = function () {
alert("Request failed");
};
因此
subscribeonload
this.companyService
.put$(this.currentId, this.appMenu.currentObject)
.subscribe(selectedCompany => {
this.appMenu.currentObject = selectedCompany
});
如果你喜欢隐喻：
银行里有一首诗（数据库
），您的抄本中有一份诗的副本（客户端应用程序，在您的应用程序中是Angular应用程序
）
但是，您希望编辑您的文案和银行中的一些诗行
然后你打电话给银行账户管理员（this.companyService
）将你的行（.put
）放入现有的诗篇（this.currentId，this.appMenu.currentObject
）中，然后你等待银行账户管理员（.subscribe
）直到她/他更新银行的诗篇
更新：
@angular/common/http中的HttpClient提供了一个简化的客户端http
基于XMLHttpRequest的角度应用程序API
浏览器公开的接口。HttpClient的其他好处
包括可测试性功能、类型化请求和响应对象，
请求和响应拦截、可观察的API和简化的
错误处理
XMLHttpRequest或XHR是用于客户端和服务器之间通信的javascript API。使用XMLHttpRequest
（XHR）与服务器交互的对象。您可以从数据库中检索数据
无需进行完整页面刷新的URL。这将启用网页
只更新页面的一部分而不中断用户的工作
做。XMLHttpRequest在AJAX编程中大量使用
与它的名字相反，XHR可以用来接收JSON、HTML、纯文本以及XML
以及使用以下各项的示例：
// 1. Here we are creating a new XMLHttpRequest object
let xhr = new XMLHttpRequest();
// 2. Then we set its configuration: request of GET type for the URL /somePage/anotherPage
xhr.open('GET', '/somePage/anotherPage');
// 3. We are sending the request over the network
xhr.send();
// 4. Then this rows will be called after the response is received from the
// server to the client
xhr.onload = function () {
if (xhr.status != 200) { // see what HTTP status of the response is come
alert(`Error ${xhr.status}: ${xhr.statusText}`); // e.g. 404: Not Found
} else { // show the result
alert(`Great, got ${xhr.response.length} bytes`); // responseText is the server
}
};
// Get progress from XMLHttpRequest
xhr.onprogress = function (event) {
if (event.lengthComputable) {
alert(`We are received ${event.loaded} of ${event.total} bytes`);
} else {
alert(`We are received ${event.loaded} bytes`); // no Content-Length
}
};
xhr.onerror = function () {
alert("Request failed");
};
所以subscribe
HTTPClientonloadXMLHttpRequest