Multiple TS Changes and Improvements

[YourWishes]

Refer to #289
Also see #288

Also, is there a preferred prettier config? I went with --single-quote --trailing-comma es5, although it's done some aesthetic damage to my WebhookMap which could be a tad confusing to glance at, thoughts?

Pull Request Fixes

Fixed commit title to omit trailing period
Ran through prettier to correct semicolon and comma inconsistencies.

Definition Changes

Added missing property id to ICarrierService
Added Interface for ICart, ICartLineItem and IDeletedItem
Added WebhookType map, e.g. WebhookType<'products/create'> will yeild IProduct
Added various types for shipping carrier callbacks.

[coveralls]

Coverage remained the same at 100.0% when pulling a348722 on YourWishes:master into ee36abe on MONEI:master.

[coveralls]

Coverage remained the same at 100.0% when pulling a348722 on YourWishes:master into ee36abe on MONEI:master.

[coveralls]

Coverage remained the same at 100.0% when pulling a348722 on YourWishes:master into ee36abe on MONEI:master.

[coveralls]

Coverage remained the same at 100.0% when pulling a348722 on YourWishes:master into ee36abe on MONEI:master.

[lpinca]

No trailing commas please. Single quote is ok and consistent with current style.

[YourWishes]

No trailing commas please. Single quote is ok and consistent with current style.

alright thanks for clearing up, I ran the defintions through prettier with the updated config, no changes to commit though.

[lpinca]

Rubber stamp LGTM. Are there breaking changes? I mean, do these types work with TypeScript < 3? Is there a chance that this will break people builds? (I don't use TypeScript)

[YourWishes]

The map for the webhooks uses conditional types, according to the docs these were introduced in TS 2.8.x.

Reverting back to version 2.0.10 shows that it will still compile without errors when not being used, the only time an error will be thrown is when attempting to use the new maps in a format that is unexpected.

TS 2.0.10

type T = Shopify.WebhookType<'products/create'>;
let x = request.get() as T;//T is type of 'products/create' not the expected IProduct
x.id;//Will result in an error since TS thinks x is a string

Without use of Webhook Types Map (How it's currently being handled)

let x = request.get() as IProduct;//Implicit cast of any to IProduct
x.id;//No error

TS 2.8.x+

type T = Shopify.WebhookType<'products/create'>;
let x = request.get() as T;//T is type of IProduct
x.id;//Works without error.

Benefits;

const addWebhook = <T extends WebhookTopic>(hook:T, express:Express, cb:(o:WebhookType<T>) => void) => {
  express.post(`/webhook/${hook}`, (req,res) => {
    cb(req.get() as WebhookType<T>);
  });
}

addWebhook('products/create', app, product => {
  product;//Typeof IProduct
  product.id;//No errors, returns a number.
});

addWebhook('checkouts/create', app, checkout => {
  checkout;//Typeof ICheckout
});

[lpinca]

Thank you.