TypeScript Tutorial in Hindi #39 - Override Function with Decorator in TypeScript

function updatedSum(target:any,key:string,descriptor:PropertyDescriptor){

descriptor.value=function sum(x:number,y:number){

let output=x+y

return "the output of "+x+" and "+y+ " is : " + output

}

}

class CustomMaths1{

@updatedSum

sum(x:number,y:number){

return x+y

}

}

var cm2= new CustomMaths1();

console.log(cm2.sum(10,20));

"use strict";

var __decorate = (this && this.__decorate) || function (decorators, target, key, desc) {

var c = arguments.length, r = c < 3 ? target : desc === null ? desc = Object.getOwnPropertyDescriptor(target, key) : desc, d;

if (typeof Reflect === "object" && typeof Reflect.decorate === "function") r = Reflect.decorate(decorators, target, key, desc);

else for (var i = decorators.length - 1; i >= 0; i--) if (d = decorators[i]) r = (c < 3 ? d(r) : c > 3 ? d(target, key, r) : d(target, key)) || r;

return c > 3 && r && Object.defineProperty(target, key, r), r;

};

function updatedSum(target, key, descriptor) {

descriptor.value = function sum(x, y) {

let output = x + y;

return "the output of " + x + " and " + y + " is : " + output;

};

}

class CustomMaths1 {

sum(x, y) {

return x + y;

}

}

__decorate([

updatedSum

], CustomMaths1.prototype, "sum", null);

var cm2 = new CustomMaths1();

console.log(cm2.sum(10, 20));