To dynamically change meta tags before Angular 2 site is scraped,
we can use the following approach : Create a service first then inject the service into the components then call the service’s methods to update the meta tags with the appropriate values based on the current page or user interaction.
This is done in the component’s lifecycle hooks or in response to user events.
After that the service’s methods will update the meta tags in the DOM by accessing the document.head element and modifying the <meta> tags.
This can be done by creating new <meta> tags with the desired attributes or by updating the existing ones.
Let’s take the example :
mport { Injectable } from '@angular/core';
@Injectable({
providedIn: 'root', // This won't work in Angular 2, so remove it for Angular 2
})
export class MetaTagsService {
updateTitle(title: string) {
document.title = title;
}
updateDescription(description: string) {
const descriptionMeta = document.querySelector('meta[name="description"]');
if (descriptionMeta) {
descriptionMeta.setAttribute('content', description); // Correct DOM manipulation method
/*Reasons to use setAttribute(): When you directly set name or content as properties of the meta element, you are modifying DOM element properties, not necessarily the HTML attributes. For most HTML elements, these properties correspond to attributes, but this is not always true for all elements.*/
} else {
const newMeta = document.createElement('meta');
newMeta.setAttribute('name', 'description');
newMeta.setAttribute('content', description);
document.head.appendChild(newMeta);
}
}
}
