Challenges in designing components in Angular 2.0 and beyond

Question

Challenges in designing components in Angular 2.0 and beyond

Issue at hand - There are two input controls on the same page, each belonging to separate components. When a value is entered into the first input box, it calculates the square value and updates the second input control accordingly. Conversely, if the value in the second text box is changed, it calculates the square value and updates the first input control. How can I design the component structure in Angular 8 to meet this requirement?

angular typescript components

Answer 1

Answer №1

By utilizing ngmodal and performing value calculations in the TS file, you can easily transfer values between HTML and TypeScript. The ngModal feature facilitates the seamless exchange of values from HTML to TypeScript and back again.

Answer 2

By utilizing ngmodal and performing value calculations in the TS file, you can easily transfer values between HTML and TypeScript. The ngModal feature facilitates the seamless exchange of values from HTML to TypeScript and back again.

Answer 3

Answer №2

Let's begin by addressing the implementation issue before delving into potential solutions.

The Issue at Hand

The problem arises when altering the value in the first textbox triggers the ngOnChange() lifecycle hook, calculates the square value, and updates the second textbox. However, updating the value in the second textbox subsequently triggers ngOnChange() again, prompting further changes and updates in an endless loop.

A Possible Solution

Constructing the Component Design Structure

child.component.html

<input type="text" name="name1" id="txtName2" [(ngModel)]="childText" (change)="valuechange2($event.target.value)" />

child.component.ts

import { Component, Input, OnChanges, SimpleChange, SimpleChanges, Output, EventEmitter } from '@angular/core';

    @Component({
        selector: 'child-component',
        templateUrl: './child.component.html'
    })
    export class ChildComponent implements OnChanges {
        @Input() childText: number;
        @Output() text2Change: EventEmitter<number> = new EventEmitter<number>();
        constructor() { }
        ngOnChanges(changes: SimpleChanges) {
            let currentVal = changes.childText.currentValue;
            let previousVal = changes.childText.previousValue;
            if (currentVal != previousVal) {
                this.childText = currentVal * currentVal;
            }
        }
        valuechange2(val: number) {
            this.text2Change.emit(val);
        }
    }

Child2.component.html

<input type="text" name="name1" id="txtName3" [(ngModel)]="childText" (change)="valuechange2($event.target.value)" />

Child2.component.ts

import { Component, Input, OnChanges, SimpleChange, SimpleChanges, Output, EventEmitter } from '@angular/core';

@Component({
    selector: 'child1-component',
    templateUrl: './child1.component.html'
})
export class Child1Component implements OnChanges {
    @Input() childText: number;
    @Output() text2Change: EventEmitter<number> = new EventEmitter<number>();

    constructor() { }
    ngOnChanges(changes: SimpleChanges) {
        let currentVal = changes.childText.currentValue;
        let previousVal = changes.childText.previousValue;
        if (currentVal != previousVal) {
            this.childText = currentVal * currentVal;
        }
    }
    valuechange2(val: number) {
        this.text2Change.emit(val);
    }
}

Parent Component

app.component.html

<child-component [childText]="text1" (text2Change)="childChange($event)"></child-component>
<child1-component [childText]="text2" (text2Change)="child1Change($event)"></child1-component>

app.component.ts

 import { Component, OnChanges, SimpleChanges, OnInit } from '@angular/core';
    import { of, merge } from 'rxjs';
    import { mergeMap, delay } from 'rxjs/operators';

    @Component({
      selector: 'app-root',
      templateUrl: './app.component.html',
      styleUrls: ['./app.component.scss']
    })
    export class AppComponent implements OnChanges, OnInit, OnChanges {
      title = 'my-app';

      text1: number;
      text2: number;

      ngOnChanges(changes: SimpleChanges) {
        console.log(changes);
      }

      childChange(child: number) {
        this.text2 = child;
      }
      child1Change(child: number) {
        this.text1 = child;
      }
    }

Answer 4

Let's begin by addressing the implementation issue before delving into potential solutions.

The Issue at Hand

The problem arises when altering the value in the first textbox triggers the ngOnChange() lifecycle hook, calculates the square value, and updates the second textbox. However, updating the value in the second textbox subsequently triggers ngOnChange() again, prompting further changes and updates in an endless loop.

A Possible Solution

Constructing the Component Design Structure

child.component.html

<input type="text" name="name1" id="txtName2" [(ngModel)]="childText" (change)="valuechange2($event.target.value)" />

child.component.ts

import { Component, Input, OnChanges, SimpleChange, SimpleChanges, Output, EventEmitter } from '@angular/core';

    @Component({
        selector: 'child-component',
        templateUrl: './child.component.html'
    })
    export class ChildComponent implements OnChanges {
        @Input() childText: number;
        @Output() text2Change: EventEmitter<number> = new EventEmitter<number>();
        constructor() { }
        ngOnChanges(changes: SimpleChanges) {
            let currentVal = changes.childText.currentValue;
            let previousVal = changes.childText.previousValue;
            if (currentVal != previousVal) {
                this.childText = currentVal * currentVal;
            }
        }
        valuechange2(val: number) {
            this.text2Change.emit(val);
        }
    }

Child2.component.html

<input type="text" name="name1" id="txtName3" [(ngModel)]="childText" (change)="valuechange2($event.target.value)" />

Child2.component.ts

import { Component, Input, OnChanges, SimpleChange, SimpleChanges, Output, EventEmitter } from '@angular/core';

@Component({
    selector: 'child1-component',
    templateUrl: './child1.component.html'
})
export class Child1Component implements OnChanges {
    @Input() childText: number;
    @Output() text2Change: EventEmitter<number> = new EventEmitter<number>();

    constructor() { }
    ngOnChanges(changes: SimpleChanges) {
        let currentVal = changes.childText.currentValue;
        let previousVal = changes.childText.previousValue;
        if (currentVal != previousVal) {
            this.childText = currentVal * currentVal;
        }
    }
    valuechange2(val: number) {
        this.text2Change.emit(val);
    }
}

Parent Component

app.component.html

<child-component [childText]="text1" (text2Change)="childChange($event)"></child-component>
<child1-component [childText]="text2" (text2Change)="child1Change($event)"></child1-component>

app.component.ts

 import { Component, OnChanges, SimpleChanges, OnInit } from '@angular/core';
    import { of, merge } from 'rxjs';
    import { mergeMap, delay } from 'rxjs/operators';

    @Component({
      selector: 'app-root',
      templateUrl: './app.component.html',
      styleUrls: ['./app.component.scss']
    })
    export class AppComponent implements OnChanges, OnInit, OnChanges {
      title = 'my-app';

      text1: number;
      text2: number;

      ngOnChanges(changes: SimpleChanges) {
        console.log(changes);
      }

      childChange(child: number) {
        this.text2 = child;
      }
      child1Change(child: number) {
        this.text1 = child;
      }
    }

Challenges in designing components in Angular 2.0 and beyond

Answer №1

Answer №2

Similar questions

Dynamically Disabling Form Control in Angular 2

Struggling to connect JSON information to a dynamically loaded sub-component

Tips for accessing Firebase document fields with Angular Firestore (version 7)

Identify when a click occurs outside of a text input

Exploring the Realm of Javacript Template Literal Capabilities

Guide on breaking a th tag as a line in a table using CSS

Firebase and Nx: Encountering issues with running emulators

Having trouble utilizing yarn to import Mapbox into TypeScript

Creating a personalized tooltip in Angular for a bubble chart with ApexCharts

Issue with ion-datetime component causing unexpected value changes when both maximum and minimum values are set

Using PrimeNG checkboxes to bind objects in a datatable

Inserting a pause between a trio of separate phrases

One question I have is how I can successfully send a value within the RxJS subscribe function

Is there a way to modify the style when a different rarity is selected in Next.JS?

Using TypeScript with Angular-UI Modals

Trouble navigating through an index of elastic data? Learn how to smoothly scroll with Typescript in conjunction with

What is the best way to incorporate CSS from node_modules into Vite for production?

The Angular component utilizes its own module to efficiently pass data to a child component within the application module

Express is experiencing issues with Angular Universal, preventing it from functioning properly

Encountering an issue in Angular 2: Unable to locate the name 'AmCharts' during ahead-of-time compilation