Develop Reference

Losing the focus on an input that appears conditionally - Angular 7 [duplicate]

I am working a front-end application with Angular 5, and I need to have a search box hidden, but on click of a button, the search box should be displayed and focused.
I have tried a few ways found on StackOverflow with directive or so, but can't succeed.
Here is the sample code:
#Component({
selector: 'my-app',
template: `
<div>
<h2>Hello</h2>
</div>
<button (click) ="showSearch()">Show Search</button>
<p></p>
<form>
<div >
<input *ngIf="show" #search type="text" />
</div>
</form>
`,
})
export class App implements AfterViewInit {
#ViewChild('search') searchElement: ElementRef;
show: false;
name:string;
constructor() {
}
showSearch(){
this.show = !this.show;
this.searchElement.nativeElement.focus();
alert("focus");
}
ngAfterViewInit() {
this.firstNameElement.nativeElement.focus();
}
The search box is not set to focus.
How can I do that?

Edit 2022:
Read a more modern way with #Cichy's answer below
Modify the show search method like this
showSearch(){
this.show = !this.show;
setTimeout(()=>{ // this will make the execution after the above boolean has changed
this.searchElement.nativeElement.focus();
},0);
}

You should use HTML autofocus for this:
<input *ngIf="show" #search type="text" autofocus />
Note: if your component is persisted and reused, it will only autofocus the first time the fragment is attached. This can be overcome by having a global DOM listener that checks for autofocus attribute inside a DOM fragment when it is attached and then reapplying it or focus via JavaScript.
Here is an example global listener, it only needs to be placed in your spa application once and autofocus will function regardless of how many times the same fragment is reused:
(new MutationObserver(function (mutations, observer) {
for (let i = 0; i < mutations.length; i++) {
const m = mutations[i];
if (m.type == 'childList') {
for (let k = 0; k < m.addedNodes.length; k++) {
const autofocuses = m.addedNodes[k].querySelectorAll("[autofocus]"); //Note: this ignores the fragment's root element
console.log(autofocuses);
if (autofocuses.length) {
const a = autofocuses[autofocuses.length - 1]; // focus last autofocus element
a.focus();
a.select();
}
}
}
}
})).observe(document.body, { attributes: false, childList: true, subtree: true });

This directive will instantly focus and select any text in the element as soon as it's displayed. This might require a setTimeout for some cases, it has not been tested much.
import { Directive, ElementRef, OnInit } from '#angular/core';
#Directive({
selector: '[appPrefixFocusAndSelect]',
})
export class FocusOnShowDirective implements OnInit {
constructor(private el: ElementRef) {
if (!el.nativeElement['focus']) {
throw new Error('Element does not accept focus.');
}
}
ngOnInit(): void {
const input: HTMLInputElement = this.el.nativeElement as HTMLInputElement;
input.focus();
input.select();
}
}
And in the HTML:
<mat-form-field>
<input matInput type="text" appPrefixFocusAndSelect [value]="'etc'">
</mat-form-field>

html of component:
<input [cdkTrapFocusAutoCapture]="show" [cdkTrapFocus]="show">
controler of component:
showSearch() {
this.show = !this.show;
}
..and do not forget about import A11yModule from #angular/cdk/a11y
import { A11yModule } from '#angular/cdk/a11y'

I'm going to weigh in on this (Angular 7 Solution)
input [appFocus]="focus"....
import {AfterViewInit, Directive, ElementRef, Input,} from '#angular/core';
#Directive({
selector: 'input[appFocus]',
})
export class FocusDirective implements AfterViewInit {
#Input('appFocus')
private focused: boolean = false;
constructor(public element: ElementRef<HTMLElement>) {
}
ngAfterViewInit(): void {
// ExpressionChangedAfterItHasBeenCheckedError: Expression has changed after it was checked.
if (this.focused) {
setTimeout(() => this.element.nativeElement.focus(), 0);
}
}
}

This is working i Angular 8 without setTimeout:
import {AfterContentChecked, Directive, ElementRef} from '#angular/core';
#Directive({
selector: 'input[inputAutoFocus]'
})
export class InputFocusDirective implements AfterContentChecked {
constructor(private element: ElementRef<HTMLInputElement>) {}
ngAfterContentChecked(): void {
this.element.nativeElement.focus();
}
}
Explanation:
Ok so this works because of: Change detection. It's the same reason that setTimout works, but when running a setTimeout in Angular it will bypass Zone.js and run all checks again, and it works because when the setTimeout is complete all changes are completed. With the correct lifecycle hook (AfterContentChecked) the same result can be be reached, but with the advantage that the extra cycle won't be run. The function will fire when all changes are checked and passed, and runs after the hooks AfterContentInit and DoCheck. If i'm wrong here please correct me.
More one lifecycles and change detection on https://angular.io/guide/lifecycle-hooks
UPDATE:
I found an even better way to do this if one is using Angular Material CDK, the a11y-package.
First import A11yModule in the the module declaring the component you have the input-field in.
Then use cdkTrapFocus and cdkTrapFocusAutoCapture directives and use like this in html and set tabIndex on the input:
<div class="dropdown" cdkTrapFocus cdkTrapFocusAutoCapture>
<input type="text tabIndex="0">
</div>
We had some issues with our dropdowns regarding positioning and responsiveness and started using the OverlayModule from the cdk instead, and this method using A11yModule works flawlessly.

In Angular, within HTML itself, you can set focus to input on click of a button.
<button (click)="myInput.focus()">Click Me</button>
<input #myInput></input>

To make the execution after the boolean has changed and avoid the usage of timeout you can do:
import { ChangeDetectorRef } from '#angular/core';
constructor(private cd: ChangeDetectorRef) {}
showSearch(){
this.show = !this.show;
this.cd.detectChanges();
this.searchElement.nativeElement.focus();
}

I'm having same scenario, this worked for me but i'm not having the "hide/show" feature you have. So perhaps you could first check if you get the focus when you have the field always visible, and then try to solve why does not work when you change visibility (probably that's why you need to apply a sleep or a promise)
To set focus, this is the only change you need to do:
your Html mat input should be:
<input #yourControlName matInput>
in your TS class, reference like this in the variables section (
export class blabla...
#ViewChild("yourControlName") yourControl : ElementRef;
Your button it's fine, calling:
showSearch(){
///blabla... then finally:
this.yourControl.nativeElement.focus();
}
and that's it.
You can check this solution on this post that I found, so thanks to -->
https://codeburst.io/focusing-on-form-elements-the-angular-way-e9a78725c04f

There is also a DOM attribute called cdkFocusInitial which works for me on inputs.
You can read more about it here: https://material.angular.io/cdk/a11y/overview

Only using Angular Template
<input type="text" #searchText>
<span (click)="searchText.focus()">clear</span>

When using an overlay/dialog, you need to use cdkFocusInitial within cdkTrapFocus and cdkTrapFocusAutoCapture.
CDK Regions:
If you're using cdkFocusInitial together with the CdkTrapFocus directive, nothing will happen unless you've enabled the cdkTrapFocusAutoCapture option as well. This is due to CdkTrapFocus not capturing focus on initialization by default.
In the overlay/dialog component:
<div cdkTrapFocus cdkTrapFocusAutoCapture>
<input cdkFocusInitial>
</div>

#john-white The reason the magic works with a zero setTimeout is because
this.searchElement.nativeElement.focus();
is sent to the end of the browser callStack and therefore executed last/later, its not a very nice way of getting it to work and it probably means there is other logic in the code that could be improved on.

Easier way is also to do this.
let elementReference = document.querySelector('<your css, #id selector>');
if (elementReference instanceof HTMLElement) {
elementReference.focus();
}

Angular not updating view on updates

I have a service where I'm listening to browser print events.
#Injectable()
export class ApplicationSession {
printStream$: Observable<boolean>;
constructor() {
this._setupPrintListener();
}
private _setupPrintListener(): void {
if (this._window.matchMedia) {
const beforePrintEvent = fromEvent(this._window, 'beforeprint')
.pipe(mapTo(true));
const afterPrintEvent = fromEvent(this._window, 'afterprint')
.pipe(mapTo(false));
this.printStream$ = merge(beforePrintEvent, afterPrintEvent).pipe(startWith(false));
}
}
}
Then, in my Component, I'm binding property to the printStream$ property of the service instance. As in,
export class ReferralComponent {
printRequested$: Observable<boolean>;
constructor(session: ApplicationSession) {
this.printRequested$ = session.printStream$;
//Observing values here
this.printRequested$.subscribe(console.log);
}
}
I use the component's printRequested$ property to create and destroy an angular component asynchronously.
<generic-angular-component *ngIf="printRequested$ | async"></generic-angular-component>
I have a child component within the ReferralComponent that has a button which triggers window.print() function. As in,
#Component({
template: `<button (click)="print()">Print</button>`
})
export class ChildComponent {
print() {
window.print();
}
}
My problem is, when I press Command/Ctrl + P from the keyboard, I see angular creating and destroying the <generic-angular-component>. However, when I trigger the window.print() via the child component button click, I can see the true/false values being passed on the stream. However, Angular doesn't seem to care about it at all. I don't see the component at all.
Here's a stackblitz reproduction.
You can either click on Print button and see that there's no Toggle Me line at the bottom left of the print preview page. Or, you can press Command/Ctrl + P and see that it (Toggle Me) is there at the bottom left.

Angular 2/Typescript Delete Object On Button Click

I have an Angular 2 app using Typescript but i am new to this, what i have is a table with a 'Delete' button,
I can pass the object data to my confirmation modal but when i 'Confirm' it, its still in my table.
delete-modal.component
import { Component, OnInit, Inject, Input } from '#angular/core';
import { TestService } from '../../ABC/TestService/TestService.service';
import { MdDialog, MdDialogRef, MD_DIALOG_DATA } from '#angular/material';
import { testModal } from 'models/test';
#Component({
selector: 'app-test',
templateUrl: './test.component.html',
styleUrls: ['./test.css']
})
export class testDeleteModalComponent implements OnInit {
#Input('test') test: testModal;
constructor(private TestService: TestService, private accountService: AccountService,
#Inject(MD_DIALOG_DATA) private dialogData: any) { }
ngOnInit() {
console.log('test', this.dialogData.beneficiary);
this.test = this.dialogData.test;
}
deleteTest() {
if (this.dialogData.test.identifier) {
// this.dialogData.beneficiary.splice(this.dialogData.beneficiary.indexOf(this.beneficiaryAnt), 1);
// this.dialogData.beneficiary.splice(this.beneficiary);
// delete this.beneficiary;
this.dialogData.test.splice(this.dialogData.test.indexOf(this.dialogData.test), 1);
} else {
this.dialogData.test.operation = 'X';
}
}
}
HTML
<button md-icon-button (click)="deleteTest()" name="deleteTestDetails">
<md-icon>delete forever</md-icon>
</button>
All other HTML is in a main component and the 'Delete' button is used as shown below
<app-test-main-page-delete-button [test]="test"></app-test-main-page-delete-button>
The 'deleteTest' method is called when the user click the confirm button.
I have also included above some ways i have tried in the IF but they always come back
... is not a function

It is good that you asked this question, my projects of three peoples also struggling with this. we have found is two ways. what i will show is two ways of doing typescriptdelete.
solution a.
because it is object, it will need identifier. First is
var objectdelete = {
identifier: 'Mydelte',
value: '168%'
}
Next what we need is now service. some people call them directives but from my experience they are the same thing. We have alert so user knows if they did not set identifier that they must go back. I do not see service on your side, i see array being deleted. if you combine the array and the service, this will then be working across whole website.
export class DeleteService
delete(objectToDelete: string) {
if (!objectToDelete.identifier) {
alert('No identifer');
}else {
// Delete from your array here.
}
}
Solution 2.
If the above does not meed your needs, our tema also experimented with interfaces in typescript. You can see them here https://www.typescriptlang.org/docs/handbook/interfaces.html
so it becomes
export class myDeleteService {
deleter: IDeleter
}
export interface IDeleter {
delete: this.delete.delete(deletE);
deleteArray: this.array =[];
}
then simply in your html it will be
<button (click)='delete(dieleter)'>Delete me!</button>
These are all common typescript behaviours for angular2/4/5 so we are hoping to become more used to them when we have hads more time to use them!

The easiest way to delete data object on button click and refresh instantly when it's done :
Your parent html has to call children like this :
<app-component [inputData]="dataTable" (inputDataChange)="resetData()"/>
Add dataTable as class variable and implement the output function :
resetData() { this.dataTable=[] }
Then in children html leave your code (you can use this changes)
<button class="fa fa-delete" (click)="deleteTest()" name="deleteTestDetails">Delete</button>
Finaly in your children ts file set your data object for each change, and implement your input function
myDataTable: any = [];
#Input set inputData(data: DataTable) {
if(data) {
this.myDataTable = data;
}}
#Output() inputDataChange: EventEmitter<any> = new EventEmitter();
deleteTest() {
this.inputDataChange.emit(true);
}
What does this code do ?
It will emit and event to the parent when the delete button is clicked, then your parent will delete the dataTable, and finally, your children input will refresh it, as setter will catch the changes and refresh the variable.
If you want to apply those rules to table changes, then simply emit your dataTable and reassign it instead of reset it.

I am in a project with and our team have struggled on this for a whiles.
First thing I will say is this, Angular has not made this an easy task, so we will attempt to ignore the framework and write pure Java instead to make our lives easyer on ourselves.
SO looking at your button, I can see that you have started on the right track.
If the button is calling your component like the following
Html/Java
<button ng-click="delete()">Click me<button>
Component.ts
function delete = deleteMethod(testIdentifier) {
var abc = this.beneficiary.beneficiaryIdentifier.test.splice(this.beneficiary.beneficiaryIdentifier.test.indexOf(testIdentifier));
component2.deleteFunction();
}
Component2.ts
Then we can pass our identifiers into our parent or child components and remove the beneficiary like so:
deleteMethod(deetle) {
this.beneficiary.removeAtIndex(testIdentifier.splice(1), 1);
}
Nice and easy looking back, but it took our team of threes a long whiles to figure that ones out.

Create custom script for DOM Manipulation

I'm currently working on an Angular 2 Project where I have a menu that should be closable by a click on a button. Since this is not heavy at all, I would like to put it outside of Angular (without using a component for the menu).
But I'm not sure of how to do it, actually I've just put a simple javascript in my html header, but shouldn't I put it somewhere else?
Also, what the code should be? Using class, export something? Currently this is my code:
var toggleMenuButton = document.getElementById('open-close-sidebar');
var contentHolder = document.getElementById('main-content');
var menuHolder = document.getElementById('sidebar');
var menuIsVisible = true;
var updateVisibility = function() {
contentHolder.className = menuIsVisible ? "minimised" : "extended";
menuHolder.className = menuIsVisible ? "open" : "closed";
}
toggleMenuButton.addEventListener('click', function() {
menuIsVisible = !menuIsVisible;
updateVisibility();
});
Finally moved to something with MenuComponent and a service, but I'm still encountering an issue.
MenuService.ts
#Injectable()
export class MenuService {
isAvailable: boolean = true;
isOpen: boolean = true;
mainClass: string = "minimised";
sidebarClass: string = "open";
updateClassName() {
this.mainClass = this.isOpen ? "minimised" : "extended";
this.sidebarClass = this.isOpen ? "open" : "closed";
}
toggleMenu(newState: boolean = !this.isOpen) {
this.isOpen = newState;
this.updateClassName();
}
}
MenuComponent.ts
export class MenuComponent {
constructor(private _menuService: MenuService) { }
public isAvailable: boolean = this._menuService.isAvailable;
public sidebarClass: string = this._menuService.sidebarClass;
toggleMenu() {
this._menuService.toggleMenu();
}
}
MenuComponent.html
<div id="sidebar" [class]="sidebarClass" *ngIf="isAvailable">
...
<div id="open-close-sidebar"><a (click)="toggleMenu()"></a></div>
The action are rightly triggered, if I debug the value with console.log, the class name are right but it didn't change the value of the class. I thought the binding was automatic. And I still do not really understand how to change it. Do I have to use Emmit like AMagyar suggested?

The advantage of using angular2 above your own implementation, greatly outweigh the marginal benefit in performance you will get from using plane JavaSccript. I suggest not going on this path.
If you however do want to continue with this, you should export a function and import and call this function inside the ngAfterViewInit of your AppComponent. The exported function should add the click EventListener and (important) set the document.getElementById variables. Because your script possibly won't be able to find those elements yet when it's loaded.
But let me emphasise once more, that angular2 is optimised for exactly these tasks, and once you get more familiar with it, it will also be a lot easier to code it.
update
For inter component communication you should immediately think about a service. Just create a service which stores the menu state and add this to your global ngModule providers array. For instance:
export class MenuService {
public get menuOpen(): boolean {
return this._menuOpen;
}
private _menuOpen: boolean;
public openMenu() : void {
this._menuOpen = true;
}
public closeMenu() : void {
this._menuOpen = false;
}
public toggleMenu() : void {
this._menuOpen = !this._menuOpen;
}
}
You can then inject this service into your menu component and bind the classes open/closed and minimized/extended to the MenuService.menuOpen.
#Component({
selector : 'menu'
template : `
<button (click)="menuService.toggleMenu()">click</button>
<div id="open-close-sidebar" [class.open]="menuService.menuOpen"></div>
`
})
export class MenuComponent {
constructor(public menuService: MenuService){}
}
For other component you can use the same logic to see if the menu is open or closed
update #2
You have to use a getter to get the value from menuService. There is only one way binding:
export class MenuComponent {
constructor(private _menuService: MenuService) { }
public get isAvailable(): boolean {
return this._menuService.isAvailable;
}
public get sidebarClass(): string {
return this._menuService.sidebarClass;
}
toggleMenu() {
this._menuService.toggleMenu();
}
}
FYI, it's better practice to use [class.open] instead of a string class name. If you want to do it like that, it will only require minimal change in your current css.

The main reason of why I want to avoid using Angular component is the
fact that my manipulation should be done over all the website and not
just the "menu" component.
You can create many components in Angular 2, it's easy and very practical.
The action will change the class on my menu (located in my menu
component) and on my main content (located outside of the component).
I don't know how to do it, and I'm not sure that this is the best
way... Maybe by binding the service value directly... –
The main content can have a child that is the Menu itself.
Take a look in this link. There are many solutions, one of them is to "emit" the child changes to the parent.
If you need an example I can provide one quickly.

angular 2 bind to component selector

I have a component that I needs to be hidden when a property is true. Is there a way to solve this within the component itself.
Example:
#Component({
selector: 'prio-tab',
changeDetection: ChangeDetectionStrategy.OnPush,
template:
`
<div [hidden]="!active">
stuff
</div>
`
})
export class PrioTabComponent {
#Input() title;
active:boolean = false;
}
Here I would like to have the actual "prio-tab" element to depend on active-flag. Not just the content inside prio-tab.
Or is it maybe possible to use itself when declaring the prio-tab tag, like this:
<prio-tab [hidden]="this.active">
stuff
</prio-tab>
I guess a working solution would be to create a reference to the prio-tab component in its parent and then go through the parent. But how would I do if I have multiple prio-tab's ?

You can use #HostBinding()
export class PrioTabComponent {
#Input() title;
#HostBinding('hidden')
active:boolean = false;
}