expand Typescript definition for window object

Question

I am working with Angular and Meteor using Typescript. When I set up a collection I normally declare a global variable (that's the why meteor does it):

Invoices = new Mongo.Collection( 'invoices' );

Now I want to add the Invoices to my typescript custom definition so that code's intellisense doesn't trip over it. However, Invoices is part of window object and I can't duplicate a module declaration.

Just adding this to my custom.d.ts file works for intellisense in my code

var Invoices: Mongo.Collection<any>;

However code doesn't like the var. It says I need to use declare module. However, I can't redeclare module Window.

So I am a bit at a loss how to do it in a correct way.

declare var Invoices: Mongo.Collection<any>; seems to work. Is that the best way? — Mattijs
– Mattijs, Commented Feb 6, 2016 at 5:18
Please, convert this comment in an answer. It's the best one for TS 1.8+. In fact, I think this is the only one which works inside a module. — JotaBe
– JotaBe, Commented Apr 24, 2017 at 15:13

SnareChops · Accepted Answer · 2016-02-06 05:41:00Z

3

In addition to Zeeshan's answer, interfaces in TypeScript are self merging. One other way you can define this variable is to add it to the Window interface by using

interface Window{
    Invoices: Mongo.Collection<any>;
}

Which can then be used with

window.Invoices = /* your collection */;

One thing to note here is that window is required in the above example, where are using Zeeshan's proposal it is not. Which to use depends on your preference of how explicit you would like your code to be. I agree that using declare var can be more convenient, but it could also leave a developer searching for what scope that variable is defined.

I am simply proposing this as it could be a valuable alternative approach, depending on your preference of explicitness.

answered Feb 6, 2016 at 5:41

SnareChops

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Zeeshan Hassan Memon · Accepted Answer · 2016-02-06 06:58:19Z

2

Yeah go with declare var Invoices: Mongo.Collection<any>;

Good Tutorial for More Understanding

Happy Helping!

edited Feb 6, 2016 at 6:58

answered Feb 6, 2016 at 5:30

Zeeshan Hassan Memon

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1 Comment

Mattijs Over a year ago

Zeeshan, with your edits you made a mistake. Code is Visual Studio Code, so not code :)

Aniruddha Das · Accepted Answer · 2016-12-23 18:26:22Z

2

Make sure the interface name is Window (W -capital ) and in your declaration you need to define small window.

interface Window{
    Invoices: Mongo.Collection<any>;
}

// somewhere in class
private myvar = window.invoice

answered Dec 23, 2016 at 18:26

Aniruddha Das

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1 Comment

Choco Over a year ago

Does this need to be added to a type definition file? Like what's the best practice here?

Mattijs · Accepted Answer · 2017-04-26 02:29:43Z

0

One thing that seems to work fine is: declare var Invoices: Mongo.Collection<any>;

answered Apr 26, 2017 at 2:29

Mattijs

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