角度 6：错误类型错误：无法读取未定义的属性'toLowerCase'

Question

我正在创建关于用户的六角 CRUD 应用程序，当我尝试添加新用户时，我收到以下错误：

这是我收到的错误：

core.js:12301 ERROR TypeError: Cannot read property 'toLowerCase' of undefined
at HttpXsrfInterceptor.push../node_modules/@angular/common/fesm5/http.js.HttpXsrfInterceptor.intercept (http.js:1718)
at HttpInterceptorHandler.push../node_modules/@angular/common/fesm5/http.js.HttpInterceptorHandler.handle (http.js:1134)
at HttpInterceptingHandler.push../node_modules/@angular/common/fesm5/http.js.HttpInterceptingHandler.handle (http.js:1769)
at MergeMapSubscriber.project (http.js:974)
at MergeMapSubscriber.push../node_modules/rxjs/_esm5/internal/operators/mergeMap.js.MergeMapSubscriber._tryNext (mergeMap.js:61)
at MergeMapSubscriber.push../node_modules/rxjs/_esm5/internal/operators/mergeMap.js.MergeMapSubscriber._next (mergeMap.js:51)
at MergeMapSubscriber.push../node_modules/rxjs/_esm5/internal/Subscriber.js.Subscriber.next (Subscriber.js:54)
at Observable._subscribe (scalar.js:5)
at Observable.push../node_modules/rxjs/_esm5/internal/Observable.js.Observable._trySubscribe (Observable.js:43)
at Observable.push../node_modules/rxjs/_esm5/internal/Observable.js.Observable.subscribe (Observable.js:29)

这是添加用户组件 html ：

<div class="container add-user">
<div class="col-md-6">
<h2 class="text-center">Add User</h2>
<form [formGroup]="addForm" (ngSubmit)="onSubmit()">
<div class="form-group">
<label for="email">Email address:</label>
<input type="email" formControlName="email" placeholder="Email" name="email" class="form-control" id="email">
</div>
<div class="form-group">
<label for="firstName">First Name:</label>
<input formControlName="firstName" placeholder="First Name" name="firstName" class="form-control" id="firstName">
</div>
<div class="form-group">
<label for="lastName">Last Name:</label>
<input formControlName="lastName" placeholder="Last name" name="lastName" class="form-control" id="lastName">
</div>
<button class="btn btn-success">Update</button>
</form>
</div>
</div>

这是 ts 文件：

import { Component, OnInit } from '@angular/core';
import {FormBuilder, FormGroup, Validators} from '@angular/forms';
import {UserService} from '../service/user.service';
import {first} from 'rxjs/operators';
import {Router} from '@angular/router';
@Component({
selector: 'app-add-user',
templateUrl: './add-user.component.html',
styleUrls: ['./add-user.component.scss']
})
export class AddUserComponent implements OnInit {
constructor(private formBuilder: FormBuilder, private router: Router, private userService: UserService) { }
addForm: FormGroup;
ngOnInit() {
this.addForm = this.formBuilder.group({
id: [],
email: ['', Validators.required],
firstName: ['', Validators.required],
lastName: ['', Validators.required]
});
}
onSubmit() {
this.userService.createUser(this.addForm.value)
.subscribe( data => {
this.router.navigate(['list-user']);
});
}
}

以下是用户服务：

import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { User } from '../model/user.model';
@Injectable({
providedIn: 'root'
})
export class UserService {
constructor(private http: HttpClient) { }
baseUrl: 'http://locahost:4200/users';
getUsers() {
return this.http.get<User[]>(this.baseUrl);
}
getUserById(id: number) {
return this.http.get<User>(this.baseUrl + '/' + id);
}
createUser(user: User) {
return this.http.post(this.baseUrl, user);
}
updateUser(user: User) {
return this.http.put(this.baseUrl + '/' + user.id, user);
}
deleteUser(id: number) {
return this.http.delete(this.baseUrl + '/' + id);
}
}

我尝试了不同的方法，但无法解决问题:)

我在应用程序中做错了什么？ 任何帮助将不胜感激，谢谢

Answer 1

更改

baseUrl: 'http://locahost:4200/users';

自

baseUrl= 'http://locahost:4200/users';

因为 baseUrl 的类型是字符串

Answer 2

错误已解决!!错误是由于冒号造成的：

baseUrl: 'http://locahost:4200/users';

使用"="代替"："，因为baseUrl是字符串。

baseUrl='http://locahost:4200/users';