I need to Add multiple language support for my Angular 4 Application.I need to know the best approach to achieve this.
You can use ngx-translate which is the standard library for internationalization in Angular 2+
You can import the library and create a set of json files which contains the translations and put it inside the assets folder.
Then you can refer it in the HTML. say for example.
en.json
has,
"guest.first-name": "first Name",
where first one is the key and second is the value to be displayed . and you can refer in the html as,
<input [label]="'guest.first-name' | translate" type="text" name="form_name" [(ngModel)]="firstName" required="required" ></input>