Go Interface property is undefined

Go Interface property is undefined

By : Joble Jose
Date : October 17 2020, 06:10 AM
Hope that helps There are a couple of problems here:
You can't call a method on an empty interface (interface{}) because the empty interface has no methods defined.
code :
type User interface {
    Password() string
type userResp struct {
  user User
return ur.user.Password()

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GWT Interface woes : Breaking on exception: TypeError: Cannot read property 'getRestWrapper' of undefined

GWT Interface woes : Breaking on exception: TypeError: Cannot read property 'getRestWrapper' of undefined

By : hari ganesh Krishna
Date : March 29 2020, 07:55 AM
Does that help I am writing a GWT app using Libgdx & having some difficulties loading the correct rest library at runtime. , Working change:
code :
public ApplicationListener getApplicationListener () {

        setLoadingListener(new LoadingListener(){

            public void beforeSetup() {
                // TODO Auto-generated method stub


            public void afterSetup() {
                // TODO Auto-generated method stub
                wrapper = new GWTWrapper();

            return client;
Angular2 beta , using interface all the time undefined property

Angular2 beta , using interface all the time undefined property

By : Supritha Chandra
Date : March 29 2020, 07:55 AM
Hope this helps , You defined interface for the user
code :
export interface UserInterface {
    country_name: string,
    password: string,
    email: string,
export class App {

    newUser: User;

    constructor() {
        this.newUser = new User();
        this.newUser.email = 'test@asd.com'
export class User implements UserInterface {}
Typescript Interface Optional Method Property Undefined

Typescript Interface Optional Method Property Undefined

Date : March 29 2020, 07:55 AM
Any of those help If you state markDamaged?: DamageLogger, you mean that a Book may or may not have a markDamaged property. The compiler then forces you to check that a Book (including myBook) actually has markDamaged before it will let you call it. This check is only enabled when the --strictNullChecks compiler option is set.
This works
code :
interface Book {
    markDamaged: DamageLogger
interface DamageLogger {
    (reason: string): void

let myBook: Book = {
    markDamaged: (reason: string) => console.log('Damaged: ' + reason)
// myBook: Book; it definitely has markDamaged
myBook.markDamaged('missing back cover')
interface Book { markDamaged?: DamageLogger }
// ...
// myBook: Book; Books do not definitely have markDamaged
if(myBook.markDamaged) {
    // Now we know it's there, we can call it
interface Book { markDamaged?: DamageLogger }
// don't say it's a Book
// inferred: myBook: { markDamaged: (reason: String) => void }
// TypeScript's type system is structural, not nominal
// The identity of a type is in it's structure, not name
// myBook's type says that it definitely has markDamaged
let myBook = { markDamaged: (reason: String) => console.log('Damaged: ' + reason) }

function read(b: Book) {}
// myBook's type is a subtype of Book, because a Book can be missing markDamaged but myBook definitely has it.
Property that have interface is undefined?

Property that have interface is undefined?

By : George Murphy
Date : March 29 2020, 07:55 AM
I think the issue was by ths following , There are two issues first of all, it should be [(ngModel)] with safe navigation operator
code :
<input [(ngModel)]="customer?.customerinfo?.code">
customer : Customer = {};
<input [(ngModel)]="customer?.customerinfo?.code">
Angular: Cannot read property of undefined when using nested properties in interface

Angular: Cannot read property of undefined when using nested properties in interface

By : Abhishek Shekhar
Date : March 29 2020, 07:55 AM
may help you . Your food is initialized with {}. Means that the properties have their default values. Because you also have a property name nutrients which is optional, it's default value is undefined. You need to initialize it as well like
code :
food = { nutrients: {} } as Food;
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