Typescript: How to declare an interface when also importing a library?

Question

I used stackoverflow How do you explicitly set a new property on `window` in TypeScript? to extend window. The code looks like the following:

interface Window { appConfig: any; }
window.appConfig = window.appConfig || {};

Everything works fine.

When i add the line

import _ = require('lodash');

I get an error

Error TS2339: Property 'appConfig' does not exist on type 'Window'.

How can i fix this issue?

I work with typescript 1.6.2

for window i usually just make it an any instead of trying to extend it. (<any>window).appConfig = (<any>window).appConfig || {}; Here is a possible duplicate stackoverflow.com/questions/12709074/… — Tony
– Tony, Commented Nov 3, 2015 at 16:53
this is not a duplicate. I am not asking about how to extend window. I am asking about why the import statement brings the error — David Michael Gang
– David Michael Gang, Commented Nov 3, 2015 at 16:55
have you tried doing the import above the interface? maybe lodash is overwriting or creating their own interface for window? — Tony
– Tony, Commented Nov 3, 2015 at 16:57

David Sherret · Accepted Answer · 2015-11-03 17:10:52Z

4

When using external modules, interfaces found in .ts files won't be merged with interfaces found in .d.ts files. So in this case, it's not working because the Window interface in the .ts file isn't merged with the Window interface found in lib.d.ts. That's due to the nature of external modules.

To fix it, move...

interface Window { appConfig: any; }

...into a definition file (.d.ts).

edited Nov 3, 2015 at 17:10

answered Nov 3, 2015 at 17:02

David Sherret

108k28 gold badges197 silver badges190 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Typescript: How to declare an interface when also importing a library?

1 Answer 1

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related