I've just installed a fresh install of Angular 2. But when I try to inject a service called TestService into a login component like this:
LoginComponent:
import {Component, Inject} from '#angular/core';
#Component({
selector: 'app-login',
template: `
{{ test.test }}
`,
styles: []
})
export class LoginComponent {
constructor(#Inject('test') private test){};
}
App
import { BrowserModule } from '#angular/platform-browser';
import { NgModule } from '#angular/core';
import { FormsModule } from '#angular/forms';
import { HttpModule } from '#angular/http';
import { AppComponent } from './app.component';
import { LoginComponent } from './login/login.component';
import {TestService} from "./test.service";
#NgModule({
declarations: [
AppComponent,
LoginComponent
],
imports: [
BrowserModule,
FormsModule,
HttpModule
],
providers: [{provide: 'test', useClass:TestService}],
bootstrap: [AppComponent]
})
export class AppModule { }
TestService
import { Injectable } from '#angular/core';
#Injectable()
export class TestService {
test = 'test';
constructor() { }
}
I receive an error:
error_handler.js:47EXCEPTION: Error in ./AppComponent class AppComponent - inline template:1:25 caused by: Cannot read property 'name' of undefined
What am I doing wrong?
On view you should be using Elvis Operator. Just to make sure test property will ask on test. Currently when initial change detection occurs test.test tries to evaluate binding on view. Since initially test is undefined test.test fails.
{{ test?.test }}
Related
This is my standalone component
import { Component } from '#angular/core';
import { CommonModule } from '#angular/common';
#Component({
selector: 'app-navbar',
standalone: true,
imports: [CommonModule],
templateUrl: './navbar.component.html',
styleUrls: ['./navbar.component.scss']
})
export class NavbarComponent {
}
and this is where i have imported it (in admin module)
import { NgModule } from '#angular/core';
import { CommonModule } from '#angular/common';
import { AdminRoutingModule } from './admin-routing.module';
import { UsersComponent } from './users/users.component';
import { NavbarComponent } from '../components/navbar/navbar.component';
#NgModule({
declarations: [
UsersComponent
],
imports: [
CommonModule,
AdminRoutingModule,
NavbarComponent,
]
})
export class AdminModule { }
In my usercomponent.html template i did
<p>users works!</p>
<app-navbar></app-navbar>
When I run ng serve I got
`error NG8001: 'app-navbar' is not a known element:
If 'app-navbar' is an Angular component, then verify that it is part of this module.
If 'app-navbar' is a Web Component then add 'CUSTOM_ELEMENTS_SCHEMA' to the '#NgModule.schemas' of this component to suppress this message.
2 `
I would like to know why I have this error and how to fix it
Thanks !
If NavbarComponent is part of another module, on that module you have to export the component using exports[], and then import the module, not the component on AdminModule.
If it is not part of other module, you have to include the component on declarations[] not on imports[].
Due to the requirements of project I need to send data value dataOne in app.component.ts to its app.module.ts so that I can store it in variable moduleValue. Please refer code below and suggest how can achieve this transfer of data within files.
app.component.ts
import { Component } from '#angular/core';
#Component({
selector: 'app-root',
templateUrl: './app.component.html',
styleUrls: ['./app.component.css']
})
export class AppComponent {
title = 'formcheck';
dataOne: any;
getValues(val: any) {
console.warn(val);
this.dataOne = val;
}
}
app.module.ts
import { NgModule } from '#angular/core';
import { FormsModule } from '#angular/forms';
import { BrowserModule } from '#angular/platform-browser';
import { AppRoutingModule } from './app-routing.module';
import { AppComponent } from './app.component';
let moduleValue: any;
#NgModule({
declarations: [
AppComponent
],
imports: [
BrowserModule,
AppRoutingModule,
FormsModule
],
providers: [],
bootstrap: [AppComponent]
})
export class AppModule {}
}
I'd suggest that you declare a variable or an observable in a service, however, since you mentioned that you need to do this within the same files you might want to export a variable from your component and import it into your module like so:
app.component.ts
export class AppComponent {
title = 'formcheck';
dataOne: any;
getValues(val: any) {
console.warn(val);
this.dataOne = val;
DATA = this.dataOne;
}
}
export var DATA = '';
app.module.ts
import { NgModule } from '#angular/core';
import { FormsModule } from '#angular/forms';
import { BrowserModule } from '#angular/platform-browser';
import { AppRoutingModule } from './app-routing.module';
import { AppComponent } from './app.component';
import { DATA } from './app.component';
let moduleValue: any;
#NgModule({
declarations: [
AppComponent
],
imports: [
BrowserModule,
AppRoutingModule,
FormsModule
],
providers: [],
bootstrap: [AppComponent]
})
export class AppModule {}
}
Here is the solution using service, I used BehaviorSubject for dynamic updation of value.
https://stackblitz.com/edit/angular-9pitmh?file=src%2Fapp%2Fapp.component.ts,src%2Fapp%2Fapp.component.html,src%2Fapp%2Fapp.module.ts,src%2Fapp%2Fdata.service.ts,src%2Fapp%2Fhello.component.ts
I am looking at learning Angular 8 with the Angular CLI.
I have added two new components to a core module which i have then imported to the app module.
When I try to render the components in my app html the 'not known element' error is thrown in the console.
I am unsure as to why?
Here is my app.module.ts
import { BrowserModule } from "#angular/platform-browser";
import { NgModule } from "#angular/core";
import { AppComponent } from "./app.component";
import { NoopAnimationsModule } from "#angular/platform-browser/animations";
import { CoreModule } from "./core/core.module";
#NgModule({
declarations: [AppComponent],
imports: [BrowserModule, NoopAnimationsModule, CoreModule],
providers: [],
bootstrap: [AppComponent]
})
export class AppModule {}
My core.module.ts
import { NgModule } from "#angular/core";
import { CommonModule } from "#angular/common";
import { InputComponent } from "../input/input.component";
import { GraphComponent } from "../graph/graph.component";
#NgModule({
declarations: [InputComponent, GraphComponent],
imports: [CommonModule],
exports: [InputComponent, GraphComponent]
})
export class CoreModule {}
app.component.html
<div>
<InputComponent></InputComponent>
<GraphComponent></GraphComponent>
</div>
And an example of one of the custom components:
import { Component, OnInit } from '#angular/core';
#Component({
selector: 'app-input',
templateUrl: './input.component.html',
styleUrls: ['./input.component.scss']
})
export class InputComponent implements OnInit {
constructor() { }
ngOnInit() {
}
}
I just realised that I am not referring to the components with the correct selectors!
I should be using: app-input & app-graph in the app.component.html.
I am trying to add new module to make my angular application more modular and for lazy loading.
app.module
import { NgModule } from '#angular/core';
import { BrowserModule } from '#angular/platform-browser';
import { HttpModule,BrowserXhr } from "#angular/http";
import { LabService } from './lab/lab.service';
import { FormsModule } from '#angular/forms';
import { AppComponent } from './app.component';
import { OphistoryModule } from './Ophistory/ophistory.Module' //after adding this module ERROR is thrown
#NgModule({
imports:[
BrowserModule,
HttpModule,
FormsModule,
RouterModule.forRoot([
{path: 'labDetails/:labName',component:LabDetailsComponent},
{path:'showRoboLog/:labName',component:RoboLogComponent},
{path:'',component:LabComponent}
]),
OphistoryModule
],
declarations: [
AppComponent
],
bootstrap:[ AppComponent ]
})
export class AppModule {}
app.component
import { Component } from '#angular/core';
import { Http } from '#angular/http';
import { LabComponent } from './lab/lab.component';
import { LabService } from './lab/lab.service';
#Component({
selector: 'my-app',
template: `
<router-outlet></router-outlet>
`,
providers: [LabService]
})
export class AppComponent {
constructor() {
}
pageTitle: string = 'ABC';
}
The problem I am facing after adding the module OphistoryModule is an error message saying
my-app' is not a known element:
But when I give the same name to the selector of my newly added module it is working fine.
Here are the custom module and component
ophistory.module
import { NgModule } from '#angular/core';
import { BrowserModule } from '#angular/platform-browser'
import { OphistoryComponent } from './ophistory.component'
import {CommonModule} from '#angular/common'
#NgModule({
imports: [RouterModule.forChild([
{path: 'test',component:OphistoryComponent}
]),CommonModule],
declarations:[OphistoryComponent]
})
export class OphistoryModule {}
ophistory.component
import { Component } from '#angular/core'
import { LabService } from '../lab/lab.service'
#Component({
selector:'my-ap',
templateUrl:'./ophistory.component.html'
})
export class OphistoryComponent {
constructor (private _service:LabService){}
}
Can anyone confirm if it is a bug in angular 2 or any other solution you have?
I can't figure out how to get directives working in my app. I want to apply a directive to a component, this is it in it's simplest form.
import {Directive, HostBinding} from '#angular/core';
#Directive({
selector: '[directiveSelector]'
})
export class FirstDirective {
#HostBinding() innerText = 'not working';
}
...
import {Component} from '#angular/core';
#Component({
selector: 'home',
template: `
<h1 directiveSelector>Test</h1>`
})
export class HomeComponent {
}
...
import { BrowserModule } from '#angular/platform-browser';
import { NgModule } from '#angular/core';
import { AppComponent } from './app.component';
import { HomeModule } from "./home/home.module";
import { FirstDirective } from './directives/first.directive';
#NgModule({
imports: [
BrowserModule,
HomeModule
],
declarations: [
AppComponent,
FirstDirective
],
providers: [],
bootstrap: [AppComponent]
})
export class AppModule { }
Does anyone know what I am missing here? Home renders fine, and is a component wrapped in a module. Also, I cannot get a debugger or alert to fire off in the directive - may be a problem with the template binding?
Declare the FirstDirective in your HomeModule, that should take care of it. Here I assume that your HomeComponent is part of homemodule.
Tried leaving it out myself from a module, and it produced no error but also didn't work.