How to CREATE Constant in your Angular 5 Apps? A constant is a value that can’t be changed by the program during normal execution.
OR
Constants are of fixed values that do not change during the execution of a program. There are various types of constants. The Constant types are – Numeric, Character, Integer and many more.
And constant class looks like –
exportclass AppConstants{
public staticget baseURL(): string { return"http://localhost:4200/api"; }
}
And Use of constant in Services –
import{ Injectable } from'@angular/core';
import{HttpClient, HttpParams, HttpHeaders} from"@angular/common/http";
import{ Employee } from'./employee';
import{ AppConstants} from'../app/constants'
@Injectable()
exportclass EmployeeService{
//variable initialization
headers : any;
_baseURL : string;
//constructor initialization
constructor(private_htc:HttpClient) {
this.headers= new HttpHeaders().set('content-type', 'application/json');
this._baseURL= AppConstants.baseURL;
}
// POST employee - for creating a New employee.
addEmployee(emp:any){
var employee= {
name:emp.name,
Dep:emp.Dep,
Des:emp.Des
}
return this._htc.postEmployee>(this._baseURL+'/Employees/Add', employee, (this.headers));
}
//DELETE employee - for delete employee.
deleteEmployee(id:string){
return this._htc.deleteEmployee>(this._baseURL+'/Employees/Delete/'+id);
}
}
