For installing typescript 1.7.5, use

    npm install typescript@1.7.5



to install **globally** `npm install -g typescript@1.7.5`

to check open cmd and run 
`tsc -v`

to install it for the **specific** project you are working on change to the directory of your project 

`npm install typescript@1.7.5`

and then check your package.json file

If you are using visual studio 2017, it may be using visual studio&#39;s version of typescript.

If you have a higher version of typescript and you want to install an older version, you can Uninstall the current version by this command(optional):

    npm uninstall typescript

And then you can install the specific version you want like this for version(3.9.7):

    npm install typescript@3.9.7

for ***Globally*** **Install** or **Uninstall** you can add -g to both of the above commands.

As I understand from the [Firebase Docs][1], if a user authenticates his account with a credential, he should strictly login by using the same credential if the credential is not linked with another one yet.

In other words, if I create an account by using Google sign in, and then (after sign out) try to login with Facebook credential by using the same email that is used for Google credential, I should see this exception in logcat:

&gt; &quot;An account already exists with the same email address but different
&gt; sign-in credentials. Sign in using a provider associated with this
&gt; email address.&quot;

And yes, I get this exception unsurprisingly. But if I create an account by using Facebook, and then try to login with Google credential, the provider of this account (Facebook) is converted to Google. This time authentication does not fail but it is not the expected result. I want to associate each user with a specific credential in a way. How should I fix this? You can see the code below: 

    public class SignInActivity extends AppCompatActivity implements GoogleApiClient.OnConnectionFailedListener,
            View.OnClickListener {
    
        private static final String TAG = &quot;SignInActivity&quot;;
        private static final int RC_SIGN_IN = 9001;
    
        private GoogleApiClient mGoogleApiClient;
        private FirebaseAuth mFirebaseAuth;
        private FirebaseAuth.AuthStateListener mFirebaseAuthListener;
    
        private CallbackManager mCallbackManager;
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
    
            setContentView(R.layout.activity_sign_in);
    
            // Facebook Login
            FacebookSdk.sdkInitialize(getApplicationContext());
            mCallbackManager = CallbackManager.Factory.create();
    
            LoginButton mFacebookSignInButton = (LoginButton) findViewById(R.id.facebook_login_button);
            mFacebookSignInButton.setReadPermissions(&quot;email&quot;, &quot;public_profile&quot;);
    
            mFacebookSignInButton.registerCallback(mCallbackManager, new FacebookCallback&lt;LoginResult&gt;() {
                @Override
                public void onSuccess(LoginResult loginResult) {
                    Log.d(TAG, &quot;facebook:onSuccess:&quot; + loginResult);
                    firebaseAuthWithFacebook(loginResult.getAccessToken());
                }
    
                @Override
                public void onCancel() {
                    Log.d(TAG, &quot;facebook:onCancel&quot;);
                }
    
                @Override
                public void onError(FacebookException error) {
                    Log.d(TAG, &quot;facebook:onError&quot;, error);
                }
            });
    
            // Google Sign-In
            // Assign fields
            SignInButton mGoogleSignInButton = (SignInButton) findViewById(R.id.google_sign_in_button);
    
            // Set click listeners
            mGoogleSignInButton.setOnClickListener(this);
    
            GoogleSignInOptions gso = new GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN)
                    .requestIdToken(getString(R.string.default_web_client_id))
                    .requestEmail()
                    .build();
            mGoogleApiClient = new GoogleApiClient.Builder(this)
                    .enableAutoManage(this /* FragmentActivity */, this /* OnConnectionFailedListener */)
                    .addApi(Auth.GOOGLE_SIGN_IN_API, gso)
                    .build();
    
            // Initialize FirebaseAuth
            mFirebaseAuth = FirebaseAuth.getInstance();
    
            mFirebaseAuthListener = new FirebaseAuth.AuthStateListener() {
                @Override
                public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {
                    FirebaseUser user = firebaseAuth.getCurrentUser();
                    if (user != null) {
                        // User is signed in
                        Log.d(TAG, &quot;onAuthStateChanged:signed_in:&quot; + user.getUid());
                    } else {
                        // User is signed out
                        Log.d(TAG, &quot;onAuthStateChanged:signed_out&quot;);
                    }
                }
            };
        }
    
        @Override
        public void onStart() {
            super.onStart();
            mFirebaseAuth.addAuthStateListener(mFirebaseAuthListener);
        }
    
        @Override
        public void onStop() {
            super.onStop();
            if (mFirebaseAuthListener != null) {
                mFirebaseAuth.removeAuthStateListener(mFirebaseAuthListener);
            }
        }
    
        private void firebaseAuthWithGoogle(GoogleSignInAccount acct) {
            Log.d(TAG, &quot;firebaseAuthWithGooogle:&quot; + acct.getId());
            AuthCredential credential = GoogleAuthProvider.getCredential(acct.getIdToken(), null);
            mFirebaseAuth.signInWithCredential(credential)
                    .addOnCompleteListener(this, new OnCompleteListener&lt;AuthResult&gt;() {
                        @Override
                        public void onComplete(@NonNull Task&lt;AuthResult&gt; task) {
                            Log.d(TAG, &quot;signInWithCredential:onComplete:&quot; + task.isSuccessful());
    
                            // If sign in fails, display a message to the user. If sign in succeeds
                            // the auth state listener will be notified and logic to handle the
                            // signed in user can be handled in the listener.
                            if (!task.isSuccessful()) {
                                Log.w(TAG, &quot;signInWithCredential&quot;, task.getException());
                                Toast.makeText(SignInActivity.this, &quot;Authentication failed.&quot;,
                                        Toast.LENGTH_SHORT).show();
                            } else {
                                startActivity(new Intent(SignInActivity.this, MainActivity.class));
                                finish();
                            }
                        }
                    });
        }
    
        private void firebaseAuthWithFacebook(AccessToken token) {
            Log.d(TAG, &quot;handleFacebookAccessToken:&quot; + token);
    
            final AuthCredential credential = FacebookAuthProvider.getCredential(token.getToken());
            mFirebaseAuth.signInWithCredential(credential)
                    .addOnCompleteListener(this, new OnCompleteListener&lt;AuthResult&gt;() {
                        @Override
                        public void onComplete(@NonNull Task&lt;AuthResult&gt; task) {
                            Log.d(TAG, &quot;signInWithCredential:onComplete:&quot; + task.isSuccessful());
    
                            // If sign in fails, display a message to the user. If sign in succeeds
                            // the auth state listener will be notified and logic to handle the
                            // signed in user can be handled in the listener.
                            if (!task.isSuccessful()) {
                                Log.w(TAG, &quot;signInWithCredential&quot;, task.getException());
                                Toast.makeText(SignInActivity.this, &quot;Authentication failed.&quot;,
                                        Toast.LENGTH_SHORT).show();
                            }
    
                            else {
                                startActivity(new Intent(SignInActivity.this, MainActivity.class));
                                finish();
                            }
                        }
                    });
        }
    
        /*
        private void handleFirebaseAuthResult(AuthResult authResult) {
            if (authResult != null) {
                // Welcome the user
                FirebaseUser user = authResult.getUser();
                Toast.makeText(this, &quot;Welcome &quot; + user.getEmail(), Toast.LENGTH_SHORT).show();
    
                // Go back to the main activity
                startActivity(new Intent(this, MainActivity.class));
            }
        }
        */
    
        @Override
        public void onClick(View v) {
            switch (v.getId()) {
                case R.id.google_sign_in_button:
                    signIn();
                    break;
                default:
                    return;
            }
        }
    
        private void signIn() {
            Intent signInIntent = Auth.GoogleSignInApi.getSignInIntent(mGoogleApiClient);
            startActivityForResult(signInIntent, RC_SIGN_IN);
        }
    
        @Override
        public void onActivityResult(int requestCode, int resultCode, Intent data) {
            super.onActivityResult(requestCode, resultCode, data);
    
            mCallbackManager.onActivityResult(requestCode, resultCode, data);
    
            // Result returned from launching the Intent from GoogleSignInApi.getSignInIntent(...);
            if (requestCode == RC_SIGN_IN) {
                GoogleSignInResult result = Auth.GoogleSignInApi.getSignInResultFromIntent(data);
                if (result.isSuccess()) {
                    // Google Sign In was successful, authenticate with Firebase
                    GoogleSignInAccount account = result.getSignInAccount();
                    firebaseAuthWithGoogle(account);
                } else {
                    // Google Sign In failed
                    Log.e(TAG, &quot;Google Sign In failed.&quot;);
                }
            }
        }
    
        @Override
        public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {
            // An unresolvable error has occurred and Google APIs (including Sign-In) will not
            // be available.
            Log.d(TAG, &quot;onConnectionFailed:&quot; + connectionResult);
            Toast.makeText(this, &quot;Google Play Services error.&quot;, Toast.LENGTH_SHORT).show();
        }
    }

  [1]: https://firebase.google.com/docs/auth/android/account-linking

Authentication using Facebook at first and then Google causes an error in Firebase for Android

I&#39;m trying to use K&#225;roly Lőrentey&#39;s [B-tree based `OrderedSet`][1] in a project. However, I&#39;m running into an issue where I can&#39;t declare an unqualified `OrderedSet&lt;T&gt;` because the name conflicts between Foundation&#39;s `NSOrderedSet` (imported as `OrderedSet` in Swift 3) and `BTree`&#39;s `OrderedSet`.

    let set = OrderedSet&lt;Int&gt;()
    // error: &#39;OrderedSet&#39; is ambiguous for type lookup in this context
    // Found this candidate: Foundation.OrderedSet:3:14
    // Found this candidate: BTree.OrderedSet:12:15

To resolve this conflict, you would normally qualify the name, and that would give you `BTree.OrderedSet&lt;T&gt;`. However, the `BTree` module also contains a class named `BTree`. If I write `BTree.OrderedSet`, Swift thinks that I&#39;m referring to a type named `OrderedSet` that is nested in the `BTree.BTree` type.

    let set = BTree.OrderedSet&lt;Int&gt;()
    // error: reference to generic type &#39;BTree&#39; requires arguments in &lt;...&gt;

If I don&#39;t `import BTree`, I can&#39;t use the `BTree` name at all.

    // no import BTree
    let set = BTree.OrderedSet&lt;Int&gt;()
    // error: use of undeclared type &#39;BTree&#39;

How can I resolve this ambiguity between the `BTree` type and the `BTree` module?

  [1]: https://github.com/lorentey/BTree

How can I disambiguate a type and a module with the same name?

I recently installed Typescript 1.8 and found too many breaking issues.
So for the time being I would like to install 1.7.
Where can I get a link to down this?


How to install older version of Typescript?

<p>I recently installed Typescript 1.8 and found too many breaking issues.
So for the time being I would like to install 1.7.
Where can I get a link to down this?</p>


I have run into an issue in pre-selecting values on a dropdown list in Angular 2.   

I set an array of colours in the component which I bind successfully to the dropdown list. The issue I&#39;m experiencing is with pre-selecting a value on page init. 

The line `[selected]=&quot;car.color.id == x.id&quot;` should be selecting the value which has been set on the car model `this.car.color = new Colour(-1,&#39;&#39;);` however this only works when  I set the car colour id to the last item in the list (in this case black) `this.car.color = new Colour(4,&#39;&#39;);`  

I am using the latest version of Angular (rc3) and have experienced the same issues in rc1 and rc2. 

Here is a plunker showing the issue. 

https://plnkr.co/edit/yIVEeLK7PUY4VQFrR48g?p=preview

Another odd aspect is that when looking at the meta data Angular has set the selected value to true.

[![enter image description here][1]][1]

But the dropdown still appears empty.

[![enter image description here][2]][2]

It appears to be a seperate issue from these related questions.

https://stackoverflow.com/questions/36723173/angular-2-set-begin-value-of-select

https://stackoverflow.com/questions/35945001/binding-select-element-to-object-in-angular-2

https://stackoverflow.com/questions/33181936/how-to-use-select-option-ngfor-on-an-array-of-objects-in-angular2

Regards

Steve

**Component template**
 

       &lt;div&gt;
            &lt;label&gt;Colour&lt;/label&gt;
            &lt;div&gt;
                &lt;select [(ngModel)]=&quot;car.colour&quot;&quot;&gt;
                    &lt;option *ngFor=&quot;let x of colours&quot; [value]=&quot;x.id&quot; [selected]=&quot;car.color.id == x.id&quot;&gt;{{x.name}}&lt;/option&gt;
                &lt;/select&gt;
            &lt;/div&gt;
        &lt;/div&gt;


**Component**

    import { Component, OnInit } from &#39;@angular/core&#39;;
    import {AbstractControl,FORM_DIRECTIVES } from &#39;@angular/common&#39;;
    
    @Component({
        selector:&#39;dropdown&#39;,
        templateUrl:&#39;app/components/dropdown/dropdown.component.html&#39;,
        directives:[FORM_DIRECTIVES]
    })
    export class DropdownComponent implements OnInit
    {
        car:Car = new Car();
        colours = Array&lt;Colour&gt;();
    
        ngOnInit(): void {
    
            this.colours = Array&lt;Colour&gt;();
            this.colours.push(new Colour(-1, &#39;Please select&#39;));
            this.colours.push(new Colour(1, &#39;Green&#39;));
            this.colours.push(new Colour(2, &#39;Pink&#39;));
            this.colours.push(new Colour(3, &#39;Orange&#39;));
            this.colours.push(new Colour(4, &#39;Black&#39;));
            
            this.car = new Car();
            this.car.color = new Colour(-1,&#39;&#39;);        
        }
    }
    
    export class Car
    {
        color:Colour;
    }
    
    export class Colour
    {
        constructor(id:number, name:string) {
            this.id=id;
            this.name=name;
        }
    
        id:number;
        name:string;
    }


  [1]: http://i.stack.imgur.com/TYQxn.png
  [2]: http://i.stack.imgur.com/td0jh.png

Angular 2 - Setting selected value on dropdown list

I have a Component and a Service:

Component:
&lt;!-- begin snippet: js hide: false console: true --&gt;

&lt;!-- language: lang-js --&gt;

    export class WebUserProfileViewComponent {
        persons: Person [];
        personId: number;
        constructor( params: RouteParams, private personService: PersonService) {
              
            
               this.personId = params.get(&#39;id&#39;);
               this.persons =  this. personService.getPersons();
               console.log(this.personId);  
            }
    }

&lt;!-- end snippet --&gt;

Service: 

&lt;!-- begin snippet: js hide: false console: true --&gt;

&lt;!-- language: lang-js --&gt;

    @Injectable()
    export class PersonService {
          getPersons(){
            var persons: Person[] = [
                {id: 1, firstName:&#39;Hans&#39;, lastName:&#39;Mustermann&#39;, email: &#39;mustermann@test.com&#39;, company:&#39;Test&#39;, country:&#39;DE&#39;},
                {id: 2, firstName:&#39;Muster&#39;, lastName:&#39;Mustermann&#39;, email: &#39;mustermann@test.com&#39;, company:&#39;test&#39;, country:&#39;DE&#39;},
                {id:3, firstName:&#39;Thomas&#39;, lastName:&#39;Mustermann&#39;, email: &#39;mustermannt@tesrt.com&#39;, company:&#39;test&#39;, country:&#39;DE&#39;}
            ];
              
            return persons;
          }
    }

&lt;!-- end snippet --&gt;

I want to get the Person item with the ID (&#39;personID&#39;). The personID I get from `Routeparams`. For that I need the foreach loop? But I haven&#39;t found a solution for this.

Angular 2 TypeScript how to find element in Array

Here&#39;s what I have in fruit.ts

    export type Fruit = &quot;Orange&quot; | &quot;Apple&quot; | &quot;Banana&quot;

Now I&#39;m importing fruit.ts in another typescript file. Here&#39;s what I have


    myString:string = &quot;Banana&quot;;
    
    myFruit:Fruit = myString;


When I do

    myFruit = myString;

I get an error:

&gt; Type &#39;string&#39; is not assignable to type &#39;&quot;Orange&quot; | &quot;Apple&quot; |
&gt; &quot;Banana&quot;&#39;

How can I assign a string to a variable of custom type Fruit?

Typescript Type &#39;string&#39; is not assignable to type

I&#39;m trying to run a dev server with TypeScript and an Angular application without transpiling ts files every time. 

What I found is that I *can* run `.ts` files with `ts-node` but I want also to watch `.ts` files and reload my app/server. An example of this is the command `gulp watch`.

Thank you in advance!!

How to watch and reload ts-node when TypeScript files change

I am starting my project with Angular2 and the developers seem to recommend RXJS Observable instead of Promises.

I have achieved to retrieve a list of elements (epics) from the server.
But how can I filter the elments by using for example an id?

The following code is an extraction from my app and shows now the final working solution. Let&#39;s hope it helps someone.



	@Injectable()
	export class EpicService {

	  private url = CONFIG.SERVER + &#39;/app/&#39;;  // URL to web API

	  constructor(private http:Http) {}

	  private extractData(res:Response) {
		let body = res.json();
		return body;
	  }

	  getEpics():Observable&lt;Epic[]&gt; {
		return this.http.get(this.url + &quot;getEpics&quot;)
		  .map(this.extractData)
		  .catch(this.handleError);
	  }
	  
	  getEpic(id:string): Observable&lt;Epic&gt; {
		return this.getEpics()
		  .map(epics =&gt; epics.filter(epic =&gt; epic.id === id)[0]);
	  }
	}

	export class EpicComponent {

	  errorMessage:string;
	  epics:Epic[];
	  epic:Epic;

	  constructor(
		private requirementService:EpicService) {
	  }

	  getEpics() {
		this.requirementService.getEpics()
		  .subscribe(
			epics =&gt; this.epics = epics,
			error =&gt; this.errorMessage = &lt;any&gt;error);
	  }
	  
	  // actually this should be eventually in another component
	  getEpic(id:string) {
		this.requirementService.getEpic(id)
			.subscribe(
			epic =&gt; this.epic = epic,
			error =&gt; this.errorMessage = &lt;any&gt;error);
	  }
	}

	export class Epic {
	  id: string;
	  name: string;
	}

Thank you in advance for your help.

Simple filter on array of RXJS Observable

I have a set of angular2 components that should all get some service injected. My first thought was that it would be best to create a super class and inject the service there. Any of my components would then extend that superclass but this approach does not work.

Simplified example:

    export class AbstractComponent {
      constructor(private myservice: MyService) {
        // Inject the service I need for all components
      }
    }
    
    export MyComponent extends AbstractComponent {
      constructor(private anotherService: AnotherService) {
        super(); // This gives an error as super constructor needs an argument
      }
    }

I could solve this by injecting `MyService` within each and every component and use that argument for the `super()` call but that&#39;s definetly some kind of absurd.

How to organize my components correctly so that they inherit a service from the super class?

Inheritance and dependency injection

Trying to have some basic understanding about module and target.  

I would like to know the difference between module and target compile options in a typical tsconfig.json

&lt;pre&gt;
{
    &quot;compilerOptions&quot;: {
    	&quot;module&quot;: &quot;es6&quot;,
        &quot;sourceMap&quot;: true,
        &quot;target&quot;: &quot;es6&quot;
    }
}
&lt;/pre&gt;

What happens if I provide the following options:

module: commonjs, target: es6

module: es6, target: commonjs

module: commonjs, target: commonjs

TypeScript Compile Options: module vs target

I&#39;m currently working on a ReactJS project which uses Webpack2 and TypeScript. Everything works perfectly apart from one thing - I can&#39;t a find a way to move interfaces that I&#39;ve written myself into separate files so that they are visible to the whole application.

For prototyping purposes I initially had interfaces defined in files that use them but eventually I started adding some that were needed in multiple classes and that&#39;s when all the problems started. No matter what changes I make to my `tsconfig.json` and no matter where I put the files my IDE and Webpack both complain about not being able to find names (*&quot;Could not find name &#39;IMyInterface&#39;&quot;*). 

Here&#39;s my current `tsconfig.json` file:

```json
{
  &quot;compilerOptions&quot;: {
    &quot;baseUrl&quot;: &quot;src&quot;,
    &quot;outDir&quot;: &quot;build/dist&quot;,
    &quot;module&quot;: &quot;commonjs&quot;,
    &quot;target&quot;: &quot;es5&quot;,
    &quot;lib&quot;: [
      &quot;es6&quot;,
      &quot;dom&quot;
    ],
    &quot;typeRoots&quot;: [
      &quot;./node_modules/@types&quot;,
      &quot;./typings&quot;
    ],
    &quot;sourceMap&quot;: true,
    &quot;allowJs&quot;: true,
    &quot;jsx&quot;: &quot;react&quot;,
    &quot;moduleResolution&quot;: &quot;node&quot;,
    &quot;rootDir&quot;: &quot;src&quot;,
    &quot;forceConsistentCasingInFileNames&quot;: true,
    &quot;noImplicitReturns&quot;: true,
    &quot;noImplicitThis&quot;: true,
    &quot;noImplicitAny&quot;: false,
    &quot;strictNullChecks&quot;: true,
    &quot;suppressImplicitAnyIndexErrors&quot;: true,
    &quot;noUnusedLocals&quot;: true
  },
  &quot;exclude&quot;: [
    &quot;node_modules&quot;,
    &quot;build&quot;,
    &quot;scripts&quot;,
    &quot;acceptance-tests&quot;,
    &quot;webpack&quot;,
    &quot;jest&quot;,
    &quot;src/setupTests.ts&quot;
  ],
  &quot;types&quot;: [
    &quot;typePatches&quot;
  ]
}
```

As you can see, my `tsconfig.json` is in the root of the project directory, all source is in `./src`, I placed my custom `.d.ts` files in `./typings` and included it in `typeRoots`.

I tested it with TypeScript 2.1.6 and 2.2.0 and neither works.

One way of getting it all to work is to move my `typings` directory into `src` and then `import {IMyInterface} from &#39;typings/blah&#39;` but that doesn&#39;t feel right to me as it&#39;s not something I need to use. I want those interfaces to just be &#39;magically&#39; available throughout my application.

Here&#39;s a sample `app.d.ts` file:

```typescript
interface IAppStateProps {}
interface IAppDispatchProps {}
interface IAppProps extends IAppStateProps, IAppDispatchProps {}
```

Do I need to `export` them or maybe `declare`? I hope I don&#39;t have to wrap them in a namespace?!

## Update (October 2020)

Seeing how this question is still surprisingly popular I wanted to explain the solution in more detail.

Firstly, what could and should be confusing to people is that the interface example I gave at the end of my question actually doesn&#39;t have any `export` keywords even though I&#39;m almost certain I did have them in my files at the time of asking the question. I believe I didn&#39;t include them in the question thinking they didn&#39;t make any difference, whether they were there or not. Well, it turns out that it&#39;s not true and the `export` keyword is exactly what makes or breaks you being able to just &quot;use&quot; the interfaces versus having to explicitly `import` them.

So, the way it works in TypeScript is as follows:

If you want an interface/type that you can simply use without having to import it in the consuming module said interface must reside in a `.ts` or ideally a `.d.ts` file **without any imports or exports being present in the same file**. This is of utmost importance because as soon as you are exporting at least one thing from the same file it becomes a module and everything that is in that module must be subsequently imported by consumers.

To give you an example let&#39;s assume you want to have a type called `Dictionary` that you want to be able to use without importing. The way to declare it would be as follows:

```typescript
// types.d.ts
interface Dictionary {}
interface Foo {}
interface Bar {}
```

To use it you simply do:

```typescript
// consumer.ts
const dict: Dictionary = {};
```

However, it will no longer work if for some reason **any** of the interfaces/types in that file are exported, e.g.:

```typescript 
// types.d.ts
interface Dictionary {}
interface Foo {}
export interface Bar {}
```

It will also not work if there are imports in that file:

```typescript
// types.d.ts
import { OtherType } from &#39;other-library&#39;;

interface Dictionary {}
interface Foo extends OtherType {}
interface Bar {}
```

If that is the case the only way to be able to use the `Dictionary` type would be to also export it and then import it in the consumer:

```typescript
// types.d.ts
export interface Dictionary {}
interface Foo {}
export interface Bar {}

// consumer.ts
import { Dictionary } from &#39;./types&#39;;

const dict: Dictionary = {};
```

#### `--isolatedModules`

There is an additional quirk to keep in mind when using the `isolatedModules` modules flag in TypeScript, which, importantly, is enabled by default (and cannot be disabled) when using Create React App - `.ts` files MUST export at least one thing as otherwise you will be getting the *&quot;All files must be modules when the &#39;--isolatedModules&#39; flag is provided.&quot;* error. That means that putting the `Dictionary` interface in a `types.ts` files without the export keyword won&#39;t work. It must either be an export from a `.ts` file of be a declaration without the export in a `.d.ts` file:

```typescript
// types.d.ts
interface Dictionary {}        // works
export interface Dictionary {} // works

// types.ts
interface Dictionary {}        // doesn&#39;t work with --isolatedModules enabled
export interface Dictionary {} // works

```

N.B.  
As @dtabuenc mentions in his answer ambient modules (`.d.ts` files) are discoraged and my correction shouldn&#39;t be taken as advice. It&#39;s just an attempt at explaining how normal modules and ambient modules work in TypeScript.

Content Type	Original Author	Original Content on Stackoverflow
Question	AlvinfromDiaspar	View Question on Stackoverflow
Solution 1 - Typescript	Ajay	View Answer on Stackoverflow
Solution 2 - Typescript	crh225	View Answer on Stackoverflow
Solution 3 - Typescript	Ali Kianoor	View Answer on Stackoverflow

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Typescript Solutions

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Solution 2 - Typescript

Solution 3 - Typescript

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