Import interface in Angular 2

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In a Meteor app that uses Angular 2, I want to create a custom data type, something like this:

interface MyCustomType {
  index: number;
  value: string;

I then want to use this custom type in multiple files. I've tried creating a separate file named "mycustom.type.ts", with the following content:

export interface MyCustomType {
  index: number;
  value: string;

I then attempt to import this type so that it can be used in another file:

import MyCustomType from "./mycustom.type"

However, Atom reports the following error:

TS Error File '/.../mycustom.type.ts' is not a module ...

How should I be declaring and importing types, so that they can be used in multiple places?

You should rather import it like that :

import { MyCustomType } from './mycustom.type';

don't forget the { and }.

How To Use An Interface In Angular – Vegibit, Using an Interface as a Data Type. import { Component } from '@angular/core'; import { IGame } from './game'; selector: 'game-list', export class GameListComponent { games: IGame[] = []; Defining an Angular Interface We can make an interface to be used with our GameListComponent component class now. First, let’s add a game.ts file to the games directory.

I am adding this answer because the accepted one is incomplete. You have two issues:

One, you need to add export to your interface so that you can import it as a module:

export interface MyCustomType { index: number; value: string; }

Second you need to add the curly brackets { } to the import statement:

import { MyCustomType } from './mycustom.type';

3 Useful TypeScript Tips for Angular ―, using the interfaces import { Customer, User } from '. I recommend solution 1 over solution 2 because:. Interface based programming with TypeScript, Angular 2 & SystemJS. I'm currently trying to clean up some code in order to program against interfaces rather than against implementations but can't figure out how to.

the problem is the path you are inside the component try change ./ with ../

Interfaces in Angular 2, angular 2 interface vs class With this IEmployee interface in place, we can now import and Duration: 13:16 Posted: Jul 31, 2017 AngularJS 2 Typescript interface. I'm trying to import the User interface from UserService and use inside the LoginComponent but I don't know what I'm doing wrong

I tried all of top answers but still i get the same error then I understand moreover @edzillion issues one issue can be raise this error .

One, you need to add export to your interface so that you can import it as a module:

Second you need to add the curly brackets { } to the import statement:

Third: your interface name must be match your file name(file that interface exist in it).

Favoring Local Interfaces Over Imported Interfaces For Data , When I first started getting into Angular 2 with TypeScript, I had no idea how to handle TypeScript Interfaces for vanilla data-structures (ie, not  To use the interface as a data type, we import the interface, then use the interface name as the data type. We are back in the sample application looking at the car-list-component.ts Here, we see that we defined our cars array as any, so let’s create an interface that defines what a car is.

I think, problem is in the path:

Kindly refer below example:

If your file in another folder then refer below:

import { IPosts } from "../interfaces/iposts.type";

iposts.type.ts :

export interface IPosts {
   userId: number;
   id: number;
   title: string;
   body: string;

Creating Interfaces for Angular Services -, However, since interfaces are not compiled into the JavaScript output of TypeScript, achieving this with an Angular service is rather unintuitive. This guide will  do I just need to explicitly import the interface directly into each component? You do need to do this - keep in mind that NgModule doesn't automatically import other ECMAScript/TypeScript modules for you.

Interfaces, Interfaces. An interface is a TypeScript artifact, it is not part of ECMAScript. An interface is a way to define a contract on a function with respect to the arguments​  Use Class instead of Interface that is what I discovered after all my research. Why? A class alone is less code than a class-plus-interface. (anyway you may require a Class for data model) Why? A class can act as an interface (use implements instead of extends). Why? An interface-class can be a provider lookup token in Angular dependency injection.

Handbook - Interfaces, How to write an interface with TypeScript. let a : number[] = [1, 2, 3, 4]; let ro : ReadonlyArray <number> = a ; ro [0] = 12; // error! Index signature in type  Likewise in Angular, we may run across situations where an injected service needs to have different implementations depending on its context, a perfect candidate for an interface.

Basic Typescript for Angular: Understanding Modules, In Typescript, a module is simply a file that imports or exports something. 1 2 3 4 5 6 7 8 9 10 11 12 // app/shopping-cart/products.service.ts export Service code here } export interface Product { // Interface declarations }  This answer could also give you some additional hints: Interface based programming with TypeScript, Angular 2 & SystemJS. Hope it helps you, Thierry

  • I have the same issue but I already had the brackets { } so this didn't work for me. Any other possible solutions?
  • This answer is only part of the issue. If you want to import a module you need to set the interface as exportable - .e.g. export interface MyCustomType {
  • If you want to import you have to export. Of course. Plus, OP already exported it so I really don't see your point here.
  • What is the purpose of the curly brackets { }?
  • @alibenmessaoud for the import it describes which modules to import from the file. e.g. import { ModuleA, ModuleB, ModuleC } from './modulefile'