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Method overloading in Angular 4/2

I am now working with Angular 4. I have not found the correct solution for method overloading in Angular 2 or 4. Is it possible to implement method overloading in an Angular service class? Or I'm curious to know the details about this. Thanks in advance.

I just tried to compile the Service as shown below but found Dublicate Function Implementation Error

ApiService.ts :

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

@Injectable()
export class ApiService {

       constructor() { }

       postCall(url, data, token) { // with three parameters
                 return resultFromServer; }        

       postCall(url, data) { // with two parameters
                return resultFromServer;}          
       }

AuthenticationService.ts :

import { Injectable } from '@angular/core';
import { ApiService } from "app/_services/api.service";
import FunUtils from "app/_helper/utils";

@Injectable()
export class AuthenticationService {

    constructor(private api: ApiService) { }

    rest_login_call(userName, password) {
        let data = { username: userName, password: password };
        let url = "http://localhost:8000";
        return this.api.postCall(url, data);
    }

}
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2 answers


Instead of overloading methods, make an optional token parameter .

postCall(url, data, token?) { // with three parameters
             return resultFromServer; 
}


Hope it helps

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As with TypeScript 1.4, you can usually remove the need for overloading by using an optional parameter and union type (if you don't know the type of the parameter). The above example could be better expressed with:



postCall(url: string, data: Object, token?: string | number) {
   return resultFromServer; 
}
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