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Typescript dynamically visible class methods

By : Jill Chih
Date : September 17 2020, 03:00 AM
this one helps. First: visibility is only checked during compile time, so bear in mind that there's no way to throw an error at runtime if you want to block access to a method. If this is your use-case, try something else.
If you want compile-time checking, what you're properly really after is better types.
code :
class Foo {
   method1() {}
   method2() {}
type FooMethod2Only {
   method2: () => void;
function doSomething(foo: FooMethod2Only) {
doSomething(new Foo());

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Dynamically loading a typescript class (reflection for typescript)

By : Chetna Wadhwa
Date : March 29 2020, 07:55 AM
Any of those help I would like to be able to instantiate a typescript class where I get the class and constructor details at runtime. The function I would like to write will take in the class name and constructor parameters. , You could try:
code :
var newInstance = Object.create(window[className].prototype);
newInstance.constructor.apply(newInstance, instanceparameters);
return newInstance;
class Greeter {
    greeting: string;
    constructor(message: string) {
        this.greeting = message;
    greet() {
        return "Hello, " + this.greeting;

//instance creation here
var greeter = Object.create(window["Greeter"].prototype);
greeter.constructor.apply(greeter, new Array("World"));

var button = document.createElement('button');
button.innerText = "Say Hello";
button.onclick = function() {


Dynamically access methods of class TypeScript

By : رميس فروخ
Date : March 29 2020, 07:55 AM
To fix this issue We simply have to leave strongly typed (and checked) world, and use just a JavaScript style (which is still useful, e.g. in these cases)
code :

How do I dynamically export Class methods as standalone functions in TypeScript?

By : wl2016
Date : March 29 2020, 07:55 AM
To fix the issue you can do I am rewriting an old NPM module in TypeScript, and I ran into an interesting problem. , Yes, we can! © In "Thing" file combine default export and export:
code :
export class Thing {
    init() { }

export default new Thing();

typescript class decorator:typescript compiler doesn't recognize abstract methods

By : Andrew
Date : March 29 2020, 07:55 AM
this one helps. The problem is that a class decorator is applied to the constructor of the class, not to an instance of the class.
That is, given a constructor type Ctor like
code :
type Ctor<T> = {
    new(...args: any[]): T;
    prototype: T
function ValidationDecorator() {
  return function<T extends Ctor<BaseValidation>>(target: T) {
    // impl
const validationMap: { [k: string]: Ctor<BaseValidation> | undefined } = {};
function ValidationDecorator() {
  return function<T extends Ctor<BaseValidation>>(target: T) {
    // assuming that getValidationName is a method defined on the prototype
    validationMap[target.prototype.getValidationName()] = target;
class SomeValidation extends BaseValidation {
  public getValidationName(): string {
    return "ValidationName";

  public validation(): boolean {
    return false;

class SomeOtherValidation extends BaseValidation {
  public getValidationName(): string {
    return "OtherValidationName";
  public validation(): boolean {
    return false;
Object.keys(validationMap).forEach(k =>
  console.log(k + ": " + (validationMap[k] || { name: "oops" }).name)
// ValidationName: SomeValidation
// OtherValidationName: SomeOtherValidation
const simplerValidationMap = {
  ValidationName: (thingToValidate: any) => false,
  OtherValidationName: (thingToValidate: any) => false

Adding methods dynamically to a class in typescript

By : user3313352
Date : March 29 2020, 07:55 AM
will be helpful for those in need You should be using
extclass.prototype['modifyLogger'] = function(mylogger:any){ }
code :
interface extclass{
    modifyLogger(arg: any): void;
class Extclass { 
    test() {

interface Extclass {
    modifyLogger(): void;

class Test {
    constructor() { 
        Extclass.prototype['modifyLogger'] = function () {
        var obj = new Extclass();

var t = new Test();
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