JSDoc style comments create typescript types

[dedalusMohantyMa]

I added JSDoc annotations that can create typescript types.

If you run the script in package.json generate-types it will genereate types into the types directory.
I hope I wrote them correctly, so kindly @dedalusMohantyMa , when you see something fishy 🐟

Kindly review this, as this is my first time doing this :-)

#32

[Barsoomx]

@dedalusMohantyMa
You missed readyState property typedef which is widely used in EventSource, so i think it's crucial it is defined

[caugner]

@mpetazzoni Are these properties all mandatory? If not, you'll want to add ? behind the property name.

We get this error, because we don't pass method and debug:

error TS2345: Argument of type '{ headers: { "Content-Type": string; }; withCredentials: true; payload: string; }' is not assignable to parameter of type 'SSEOptions'.
  Type '{ headers: { "Content-Type": string; }; withCredentials: true; payload: string; }' is missing the following properties from type 'SSEOptions': method, debug

[caugner]

Opened a PR to fix these: #43.

[henges]

Yes, these properties should not be required as they all have default values supplied:

sse.js/lib/sse.js

Lines 30 to 35 in cdb9a03

	options = options || {};
	this.headers = options.headers || {};
	this.payload = options.payload !== undefined ? options.payload : '';
	this.method = options.method || (this.payload && 'POST' || 'GET');
	this.withCredentials = !!options.withCredentials;
	this.debug = !!options.debug;

[dedalusMohantyMa]

yeah sry, I was preoccupied with other work. Thanks for the fix ❤️