Whatever i do angular does not detect change on talks array. I have a handleSubmit function to send the toolbar. Toolbar use it to send the changes to parent from input field.
My app.component.ts file
import { Component, Type, OnChanges, SimpleChanges } from '#angular/core';
import { getResponse } from '../api/API';
declare module '../api/API' {
export interface NlpAPI {
getResponse(data: any): Promise<any>;
}
}
#Component({
selector: 'app-root',
templateUrl: './app.component.html',
styleUrls: ['./app.component.css'],
})
export class AppComponent implements OnChanges {
talks: string[];
title: string;
ngOnChanges(changes: SimpleChanges): void {
console.log(changes);
}
constructor() {
this.talks = [];
this.title = 'Talks';
}
ngOnInit() {
this.talks.push('Welcome to ProjectX! How can I help you?');
this.talks.push('I am a chatbot. I can help you with your queries.');
}
handleSubmit(data: any): void {
this.talks.push(data.talk);
}
messageResponse() {
// #ts-ignore: Object is possibly 'null'.
const x = document.getElementById('txt').value;
// #ts-ignore: Object is possibly 'null'.
document.getElementById('output').innerHTML =
'Your message is ' + '"' + x + '"';
}
}
My app.component.html
<!-- Toolbar -->
<app-custom-toolbar [handleSubmit]="handleSubmit"></app-custom-toolbar>
<!-- Highlight Card -->
<app-text-area [talksFromUser]="talks" [title]="title"></app-text-area>
<!-- Bottombar -->
<router-outlet></router-outlet>
My text-area.component.ts file
import { Component, Input, OnChanges, SimpleChanges } from '#angular/core';
#Component({
selector: 'app-text-area',
templateUrl: './text-area.component.html',
styleUrls: ['./text-area.component.css'],
})
export class TextAreaComponent implements OnChanges {
#Input() talksFromUser: string[] = [];
#Input() title: string = '';
constructor() {}
ngOnChanges(changes: SimpleChanges): void {
console.log(changes);
}
}
My text-area.component.html
<div class="main-text-area">
<div *ngFor="let item of talksFromUser">{{ item }}</div>
</div>
custom-toolbar.component.ts file
import { Component, Input, OnInit } from '#angular/core';
import { NgForm } from '#angular/forms';
#Component({
selector: 'app-custom-toolbar',
templateUrl: './custom-toolbar.component.html',
styleUrls: ['./custom-toolbar.component.css'],
})
export class CustomToolbarComponent implements OnInit {
talks: string[] = [];
#Input() handleSubmit!: (args: any) => void;
constructor() {}
ngOnInit(): void {}
onSubmit(f: NgForm) {
this.handleSubmit(f.value);
f.resetForm();
}
}
I tried also
this.talks = [...this.talks, data.talk]
Thank you all.
There are two issues in your code:
First one, you are calling handleSubmit("string") (so data is a string), but you are pushing data.talk, which is undefined (so talks will be [undefined, undefined, ...]). To fix it, use data:
handleSubmit(data: any): void {
this.talks.push(data); // use "data" instead of "data.talk"
}
Second one, you are using a AppComponent method into CustomToolbarComponent class. You need to keep the this scope of AppComponent. Also, you should use arrow functions:
handleSubmit = (data: any): void => {
this.talks.push(data);
}
Related
the Item file
component file
the data service file
when I test my code with console log statements it says data from service is undefined
import { Component, OnInit } from '#angular/core';
import { Item } from '../item';
import { DataService } from '../data.service';
#Component({
selector: 'app-shopping-item',
templateUrl: './shopping-item.component.html',
styleUrls: ['./shopping-item.component.css'],
providers: [DataService]
})
export class ShoppingItemComponent implements OnInit {
shoppingItemList: Item[] = [];
constructor(private dataservice: DataService){}
getItems(){
this.dataservice.getShoppingItems()
.subscribe(items =>{
this.shoppingItemList.push(items),
console.log('data from dataservice '+ this.shoppingItemList[0].itemName);
})
}
addItem(form: any){
console.log(form)
}
ngOnInit(): void {
this.getItems();
}
}
If you are receiving an array from the API call, then you need to either assign it directly to the property (1) or destructure the array into the property (2)
Currently I guess you are pushing an array inside an array, which might lead to undefined error!
import { Component, OnInit } from '#angular/core';
import { Item } from '../item';
import { DataService } from '../data.service';
#Component({
selector: 'app-shopping-item',
templateUrl: './shopping-item.component.html',
styleUrls: ['./shopping-item.component.css'],
providers: [DataService]
})
export class ShoppingItemComponent implements OnInit {
shoppingItemList: Item[] = [];
constructor(private dataservice: DataService){}
getItems(){
this.dataservice.getShoppingItems()
.subscribe(items =>{
this.shoppingItemList = items; // solution 1
// this.shoppingItemList.push(...items); // solution 2
console.log('data from dataservice '+ this.shoppingItemList[0].itemName);
})
}
addItem(form: any){
console.log(form)
}
ngOnInit(): void {
this.getItems();
}
}
I have just started with Angular and have already faced an issue: a button actually toggles the variable I need (show) but it doesn't affect the course.component
course.component must show app-csgo-course, boolean show is true because the component is visible, but after it toggles in navbar.component, nothing changes.
<app-csgo-course *ngIf="show"> </app-csgo-course>
import { NavbarComponent } from './../navbar/navbar.component';
import { Component, OnInit} from '#angular/core';
import { CourseService } from 'src/app/course.service';
#Component({
selector: 'app-course',
templateUrl: './course.component.html',
styleUrls: ['./course.component.css']
})
export class CourseComponent implements OnInit {
constructor() { }
ngOnInit(): void { }
service = new CourseService;
show = this.service.GetShow();
}
In navbar.component there's a button which toggles the "show" variable
<button (click)="ToggleShow()" >
<li class="nav-item active" id="csgo-logo">
<a href="#">
<img class="game-logo" src="assets\img\csgo-logo.png" title="Counter Strike: Global Offensive">
<!-- <a>CS:GO <span class="sr-only">(current)</span></a> -->
</a>
</li>
</button>
import { CourseService } from 'src/app/cheat.service';
import { Component, OnInit, Input, Output, } from '#angular/core';
#Component({
selector: 'app-navbar',
templateUrl: './navbar.component.html',
styleUrls: ['./navbar.component.css']
})
export class NavbarComponent implements OnInit {
service = new CourseService;
show = this.service.GetShow();
ngOnInit(): void {
}
public ToggleShow() {
this.service.show = this.service.ToggleShow();
console.log(this.service.show);
return this.service.show;
}
}
The course.service file
#Injectable({
providedIn: 'root'
})
export class CourseService {
show: boolean = true;
GetShow() {
return this.show;
}
ToggleShow() {
return this.show = !this.show
}
constructor() { }
}
}
Would appreciate your help!
Since you are new to Angular, let me break it down for you.
You need to create a BehaviorSubject to capture the event of toggle (this is called reactive programming which is a achieved using RxJS in Angular ).
Do not use new for a service, rather inject it in constructor.
course.service
#Injectable({
providedIn: 'root'
})
export class CourseService {
private show: boolean = true;
private toggle$ = new BehaviorSubject<boolean>(true);
constructor() { }
toggleEvent() {
return this.toggle$.asObservable();
}
toggleShow() {
this.show = !this.show
this.toggle$.next(this.show);
}
}
in NavbarComponent
import { CourseService } from 'src/app/cheat.service';
import { Component, OnInit, Input, Output, } from '#angular/core';
#Component({
selector: 'app-navbar',
templateUrl: './navbar.component.html',
styleUrls: ['./navbar.component.css']
})
export class NavbarComponent implements OnInit {
show = boolean;
// IMP: make sure to inject the service and not do "new CourseService;"
constructor(public service: CourseService){}
ngOnInit(): void {
this.service.toggleEvent().subscribe(showFlag => {
this.show = showFlag;
})
}
public ToggleShow(): void {
this.service.toggleShow();
}
}
in courseComponent
import { Component, OnInit} from '#angular/core';
import { CourseService } from 'src/app/course.service';
#Component({
selector: 'app-course',
templateUrl: './course.component.html',
styleUrls: ['./course.component.css']
})
export class CourseComponent implements OnInit {
show: boolean ;
// IMP: make sure to inject the service and not do "new CourseService;"
constructor(public service: CourseService){}
ngOnInit(): void {
this.service.toggleEvent().subscribe(showFlag => {
this.show = showFlag;
})
}
}
PS: I would suggest you to read about "how to unsubscribe an observable" and how it causes memory leaks. Once you get some idea, you should implement that in the above provided code as well. That's a best practice. Happy learning. Let me know if you have any more questions
I'm not sure how can I use a custom component if it's wrapper under another component.
Like:
ComponentA_withForm
|
--ComponentA1_withWrapperOfCustomInput
|
--ComponentA11_withCustomInput
if I have a structure like this:
ComponentA_withForm
|
--ComponentA11_withCustomInput
Everything's fine
But for my case (tons of async data) I need a wrapper... Is it possible somehow to do this?
Here is my fiddle code:
ComponentA:
import { Component } from '#angular/core';
import { FormBuilder } from '#angular/forms';
#Component({
selector: 'my-app',
template: `<form [formGroup]="form"><custom-input-wrapper formControlName="someInput"></custom-input-wrapper></form> <p>value is: {{formVal | json}}</p>`
})
export class AppComponent {
form = this.fb.group({
someInput: [],
});
get formVal() {
return this.form.getRawValue();
}
constructor(private fb: FormBuilder) { }
}
ComponentA1:
import { Component } from '#angular/core';
#Component({
selector: 'custom-input-wrapper',
template: '<custom-input></custom-input>',
})
export class CustomInputWrapperComponent {
constructor() { }
}
ComponentA11:
import { Component, forwardRef } from '#angular/core';
import { ControlValueAccessor, NG_VALUE_ACCESSOR } from '#angular/forms';
#Component({
selector: 'custom-input',
template: `Hey there! <button (click)="inc()">Value: {{ value }}</button>`,
providers: [{
provide: NG_VALUE_ACCESSOR,
useExisting: forwardRef(() => CustomInputComponent),
multi: true,
}],
})
export class CustomInputComponent implements ControlValueAccessor {
private value = 0;
writeValue(value: number): void {
this.value = value;
}
registerOnChange(fn: (_: any) => void): void {
this.onChangeFn = fn;
}
registerOnTouched(fn: any): void {
}
inc() {
this.value = this.value + 1;
this.onChangeFn(this.value);
}
onChangeFn = (_: any) => { };
}
And here I have a working sample:
https://stackblitz.com/edit/angular-qmrj3a
so: basically removing & refactoring code not to use CustomInputWrapperComponent makes my code working. But I need this wrapper and I'm not sure how to pass formControlName then.
I don't want a dirty solution with passing parent formGroup :)
Since you don't want a dirty solution ;) , you could just implement ControlValueAccessor in the CustomInputWrapperComponent also. That way any change in the parent will be reflected in the child, any change in the child will be reflected in the parent as well with just few lines of code.
Wrapper Component
#Component({
selector: 'custom-input-wrapper',
template: '<custom-input [formControl]="value"></custom-input>',
providers: [{
provide: NG_VALUE_ACCESSOR,
useExisting: forwardRef(() => CustomInputWrapperComponent),
multi: true,
}]
})
export class CustomInputWrapperComponent implements AfterViewInit, ControlValueAccessor {
public value = new FormControl();
constructor() { }
ngAfterViewInit() {
this.value.valueChanges.subscribe((x) => {
this.onChangeFn(x);
});
}
writeValue(value: number): void {
this.value.setValue(value);
}
registerOnChange(fn: (_: any) => void): void {
this.onChangeFn = fn;
}
registerOnTouched(fn: any): void {
}
onChangeFn = (_: any) => { };
}
Parent Template
<form [formGroup]="form"><custom-input-wrapper formControlName="someInput"></custom-input-wrapper></form> <p>value is: {{formVal | json}}</p>
I have made a stackbitz demo here - https://stackblitz.com/edit/angular-csaxcz
you cannot use formControlName on custom-input-wrapper because it doesn't implement ControlValueAccessor. implementing ControlValueAccessor on custom-input-wrapper might be a solution but it seems to be overkill. Instead pass the control from formGroup to custom-input-wrapper as an #Input() and pass the inputed formControl to custom-input
app.component
#Component({
selector: 'my-app',
template: `<form [formGroup]="form"><custom-input-wrapper [formCtrl]="form.get('someInput')"></custom-input-wrapper></form> <p>value is: {{formVal | json}}</p>`
})
export class AppComponent {
form = this.fb.group({
someInput: [],
});
get formVal() {
return this.form.getRawValue();
}
constructor(private fb: FormBuilder) { }
}
custom-input-wrapper.component
#Component({
selector: 'custom-input-wrapper',
template: '<custom-input [formControl]="formCtrl"></custom-input>',
})
export class CustomInputWrapperComponent {
#Input() formCtrl: AbstractControl;
constructor() { }
}
here is a working demo https://stackblitz.com/edit/angular-3lrfqv
I have this Angular6 component arquitecture in my app
Main component
<app-navbar></app-navbar>
<app-dashboard></app-dashboard>
Dashboard component
<app-meseros>
</app-meseros>
<app-ultimospedidos></app-ultimospedidos>
<app-modal></app-modal>
I want to call modal from navbar.component, my modal is on dashboard on component modal.component
This is what i have tried
<!--navbar.component.html -->
<a class="nav-link btn btn-primary" (click)="openModal()">Crear pedido</a>
<!--navbar.component.ts -->
import { Component, OnInit } from '#angular/core';
import { BootstrapService } from '../../services/bootstrap.service';
#Component({
selector: 'app-navbar',
templateUrl: './navbar.component.html',
styleUrls: ['./navbar.component.css']
})
export class NavbarComponent implements OnInit {
constructor(public bootstrapService: BootstrapService) {}
ngOnInit() {}
openModal() {
this.bootstrapService.toggle();
}
}
I created a service so i can communicate between my navbar.component and modal.component, this is my service
import { Injectable } from '#angular/core';
#Injectable({
providedIn: 'root'
})
export class BootstrapService {
isOpen: any = false;
constructor() {}
toggle() {
console.log(!this.isOpen);
return (this.isOpen = !this.isOpen);
}
}
Then in modal.component.ts i want to subscribe to these changes so i can launch modal on boolean value change.
import { Component, OnInit } from '#angular/core';
import { BootstrapService } from '../../services/bootstrap.service';
import { NgbModal, ModalDismissReasons } from '#ng-bootstrap/ng-bootstrap';
#Component({
selector: 'app-modal',
templateUrl: './modal.component.html',
styleUrls: ['./modal.component.css']
})
export class ModalComponent implements OnInit {
isOpen;
closeResult: string;
modalname: string;
constructor(
public modalService: NgbModal,
public bootstrapService: BootstrapService
) {}
open(content) {
// console.log(this.bootstrapService.popup);
this.modalService
.open(content, { ariaLabelledBy: 'modal-basic-title' })
.result.then(
result => {
this.closeResult = `Closed with: ${result}`;
},
reason => {
this.closeResult = `Dismissed ${this.getDismissReason(reason)}`;
}
);
}
private getDismissReason(reason: any): string {
if (reason === ModalDismissReasons.ESC) {
return 'by pressing ESC';
} else if (reason === ModalDismissReasons.BACKDROP_CLICK) {
return 'by clicking on a backdrop';
} else {
return `with: ${reason}`;
}
}
ngOnInit() {
this.bootstrapService.toggle().subscribe(isOpen => {
this.isOpen = isOpen;
console.log(isOpen);
});
}
}
Im not even able to subscribe to the change from bootstrapService, i get following error,
RROR in src/app/components/modal/modal.component.ts(41,36): error TS2339: Property 'subscribe' does not exist on type 'boolean'.
if i try to subscribe to value on service like this
this.bootstrapService.isOpen.subscribe(isOpen => {
this.isOpen = isOpen;
console.log(isOpen);
});
i get error on console from browser which says
DashboardComponent.html:1 ERROR TypeError: this.bootstrapService.isOpen.subscribe is not a function
i hope someone can shade some light on this approach, and if this is the best approach to take on this kind of implementations, thanks in advance!
Solved it, i was calling wrong EventEmitter from wrong library, this is updated working code
first i call service from component where i want to call my modal
import { Component, OnInit } from '#angular/core';
import { BootstrapService } from '../../services/bootstrap.service';
#Component({
selector: 'app-navbar',
templateUrl: './navbar.component.html',
styleUrls: ['./navbar.component.css']
})
export class NavbarComponent implements OnInit {
constructor(public bootstrapService: BootstrapService) {}
ngOnInit() {}
openModal() {
this.bootstrapService.toggle();
}
}
Then i emit my changes so i can subscribe from modal component
import { Injectable, Output, EventEmitter } from '#angular/core';
#Injectable({
providedIn: 'root'
})
export class BootstrapService {
isOpen: any = 'isOpen';
#Output() change: any = new EventEmitter();
constructor() {}
toggle() {
this.change.emit(this.isOpen);
console.log(this.isOpen);
}
}
i reference my template with `#ViewChild('crearpedido') modalInstance;`
and finally subscribe to changes, call modal on subscribe changes.
import { Component, OnInit, ViewChild } from '#angular/core';
import { BootstrapService } from '../../services/bootstrap.service';
import { NgbModal } from '#ng-bootstrap/ng-bootstrap';
#Component({
selector: 'app-modal',
templateUrl: './modal.component.html',
styleUrls: ['./modal.component.css']
})
export class ModalComponent implements OnInit {
isOpen;
closeResult: string;
#ViewChild('crearpedido') modalInstance;
constructor(
public modalService: NgbModal,
public bootstrapService: BootstrapService
) {}
ngOnInit() {
this.bootstrapService.change.subscribe(isOpen => {
this.isOpen = isOpen;
console.log(this.isOpen);
this.modalService.open(this.modalInstance);
});
}
}
Here is working repo!!
https://github.com/soyisraelortiz/componentscommunication
Why is there a problem in binding a property on the same component? I already added Input() but still doesn't work. Do i need to put Input() even though it is on the same component when binding?
//output.component.ts
import { Component, OnInit} from '#angular/core';
import { DataService } from '../data.service';
#Component({
selector: 'app-output',
templateUrl: './output.component.html',
styleUrls: ['./output.component.css']
})
export class OutputComponent implements OnInit {
data: {name: string};
datas = [];
constructor(private dataService: DataService) { }
ngOnInit(){
this.datas = this.dataService.datas;
}
}
//output.component.html
<p *ngFor="let data of datas"></p>
<p>{{data.name}}</p>
//data.service.ts
export class DataService {
datas= [];
addData(name: string){
return this.datas.push({name: name});
}
}
For same component #input API is not required. It is used when you want to pass the data from Parentcomponent to a child component.
//output.component.html
<p *ngFor="let data of dataService.datas" > // removed [data]="data" and added dataService.datas
<p>{{data?.name}}</p>
</p> //changed the position of </p>
export class OutputComponent implements OnInit {
constructor(private dataService: DataService) {}
}
export class DataService {
datas= [];
addData(name: string){
return this.datas.push({name: name}); //return keyword was missing
}
}
Just for your reference
DEMO: https://plnkr.co/edit/XlJM2LHFwlAYpQe2ancM?p=preview