angular Parameter

Angular parameters are used to pass data or values into a component, directive, or service in Angular applications. Parameters allow for dynamic behavior and customization by accepting input from the caller.

In Angular, parameters can be defined in different ways depending on the context:

1. Component Parameters: In a component, you can define parameters using the `@Input()` decorator. This allows you to receive data from a parent component into a child component. For example:

import { Component, Input } from '@angular/core';

@Component({
  selector: 'app-child',
  template: `
    <h1>{{ childData }}</h1>
  `,
})
export class ChildComponent {
  @Input() childData: string;
}

2. Directive Parameters: Similar to components, directives can also have parameters using the `@Input()` decorator. Directives are used to modify the behavior and appearance of elements. For example:

import { Directive, Input, ElementRef } from '@angular/core';

@Directive({
  selector: '[appHighlight]',
})
export class HighlightDirective {
  @Input() appHighlight: string;

  constructor(private el: ElementRef) {}

  ngOnInit() {
    this.el.nativeElement.style.backgroundColor = this.appHighlight;
  }
}

3. Service Parameters: Services in Angular can also have parameters when they are injected into other components or services. The parameters are defined in the constructor of the service. For example:

import { Injectable } from '@angular/core';

@Injectable()
export class DataService {
  constructor(private http: HttpClient) {}

  getData() {
    // Use this.http to make HTTP requests
  }
}

These are just a few examples of how parameters are used in Angular. They provide a way to pass data and customize behavior within Angular components, directives, and services.