Angular2: How to enable save button if any model value changed on edit page - angular2-template

Question

I am new for angular 2. I have a page where we can edit details of customer profile. How to enable save button if any property of has been changed. I know it is possible in angular1 by using $watch.

Answer 1

It is simple. dirty check your form if you are using #angular/forms.
create form
export class HeroDetailComponent4 {
heroForm: FormGroup;
states = states;
constructor(private fb: FormBuilder) {
this.createForm();
}
createForm() {
this.heroForm = this.fb.group({
name: ['', Validators.required ],
street: '',
city: '',
state: '',
zip: '',
power: '',
sidekick: ''
});
}
}
HTML:
<h2>Hero Detail</h2>
<h3><i>A FormGroup with multiple FormControls</i></h3>
<form [formGroup]="heroForm" novalidate>
<button (click)="submit()" [disabled]="!heroForm.dirty" type="button">Submit</button>
<div class="form-group">
<label class="center-block">Name:
<input class="form-control" formControlName="name">
</label>
</div>
<div class="form-group">
<label class="center-block">Street:
<input class="form-control" formControlName="street">
</label>
</div>
<div class="form-group">
<label class="center-block">City:
<input class="form-control" formControlName="city">
</label>
</div>
<div class="form-group">
<label class="center-block">State:
<select class="form-control" formControlName="state">
<option *ngFor="let state of states" [value]="state">{{state}}</option>
</select>
</label>
</div>
<div class="form-group">
<label class="center-block">Zip Code:
<input class="form-control" formControlName="zip">
</label>
</div>
<div class="form-group radio">
<h4>Super power:</h4>
<label class="center-block"><input type="radio" formControlName="power" value="flight">Flight</label>
<label class="center-block"><input type="radio" formControlName="power" value="x-ray vision">X-ray vision</label>
<label class="center-block"><input type="radio" formControlName="power" value="strength">Strength</label>
</div>
<div class="checkbox">
<label class="center-block">
<input type="checkbox" formControlName="sidekick">I have a sidekick.
</label>
</div>
</form>
use heroForm.dirty to check whether form data is changed. it will set to true if any control inside heroForm has been changed.
<button (click)="submit()" [disabled]="!heroForm.dirty" type="button">Submit</button>
Refer angular docs for more info

Answer 2

you can use form control validation for it.
some thing like this in html template:
<form fxLayout="column" [formGroup]="form">
<mat-form-field class="mb-1">
<input matInput [(ngModel)]="userProfileChangeModel.firstName" placeholder="نام"
[formControl]="form1.controls['fname']">
<small *ngIf="form1.controls['fname'].hasError('required') && form1.controls['fname'].touched"
class="mat-text-warn">لطفا نام را وارد نمایید.
</small>
<small *ngIf="form1.controls['fname'].hasError('minlength') && form1.controls['fname'].touched"
class="mat-text-warn">نام باید حداقل 2 کاراکتر باشد.
</small>
<small *ngIf="form1.controls['fname'].hasError('pattern') && form1.controls['fname'].touched"
class="mat-text-warn">لطفا از حروف فارسی استفاده نمائید.
</small>
</mat-form-field>
<mat-card-actions>
<button mat-raised-button (click)="editUser()" color="primary" [disabled]="!form1.valid" type="submit">
ذخیره
</button>
</mat-card-actions>
</form>
and like this in ts file:
this.form = this.bf.group({
fname: [null, Validators.compose([
Validators.required,
Validators.minLength(2),
Validators.maxLength(20),
Validators.pattern('^[\u0600-\u06FF, \u0590-\u05FF]*$')])],
});
if:
[disabled]="!form1.valid"
is valid save button will be active
bast regards.

Answer 3

You can use disabled option like below :
<button [disabled]="isInvalid()" type="button" (click) = "searchClick()" class="button is-info">
<span class="icon is-small">
<i class="fa fa-search" aria-hidden="true"></i>
</span>
<span>Search</span>
</button>
you can create isInvalid() in your ts file and check if that property is empty or not and return that boolean value

Answer 4

and for hide button on a state you can use *ngIf in line directive.

Answer 5

This worked for me, pls try.
In your html,
<input type="text" [ngModel]="name" (ngModelChange)="changeVal()" >
<input type="text" [ngModel]="address" (ngModelChange)="changeVal()" >
<input type="text" [ngModel]="postcode" (ngModelChange)="changeVal()" >
<button [disabled]="noChangeYet" (click)="clicked()" >
<span>SUBMIT</span>
</button>
In your component
export class customer implements OnInit {
name: string;
address: string;
postcode: string;
noChangeYet:boolean = true;
constructor() {}
changeVal(){ // triggers on change of any field(s)
this.noChangeYet = false;
}
clicked(){
// your function data after click (if any)
}
}
Hope this is what you need.

Answer 6

Finally I resolved this issue.
import { Component, Input, Output, OnInit, AfterViewInit, EventEmitter, ViewChild } from '#angular/core';
#Component({
selector: 'subscribe-modification',
templateUrl: './subscribe.component.html'
})
export class SampleModifyComponent implements OnInit, AfterViewInit {
disableSaveSampleButton: boolean = true;
#ViewChild('sampleModifyForm') sampleForm;
ngAfterViewInit() {
setTimeout(() => {
this.sampleForm.control.valueChanges.subscribe(values => this.enableSaveSampleButton());
}, 1000);
}
enableSaveSampleButton() {
console.log('change');
this.disableSaveSampleButton = false;
}
}
HTML
<button id="btnSave" class="btn btn-primary" (click)="save()" />