Re-write LightWallet and MWC in Typescript. Using modern packages.

[adilwali]

This is an experimental branch that considers upgrading core packages and restructuring the core LW application architecture.

ONGOING TODO LIST:

• Split up event types inside the lightwallet instead of bwsEvent for everything. (Ex. Local:Tx:Broadcast) [Split up 'bwsEvent' into relevant component events that can be processed separately. #213]
• More efficiently fetch data on specific event types. (Today, the application re-fetches huge chunks of data in most cases.) [More intelligently and efficiently act on relevant events. #214]
• WalletDetails Page is loaded twice. (Fires all IonViewDidLoad events twice.) [WalletDetails page is loaded Twice.  #197]
• Gracefully handle unauthorized responses from MWS. [Gracefully handle unauthorized responses from MWS. #198]
• Gracefully handle the case of MWC being down. [Gracefully handle not being able to connect to MWS. #199]
• ErrorToast is not showing up consistently in the case of errors in promise chains. [ ErrorToast is not showing up consistently in the case of errors in promise chains. #200]
• LW 2.0 should Gracefully handle insufficient funds. [LW should gracefully handle insufficient funds.  #203]
• MWS should better handle the case when there are not enough inputs to send a TX [LW should gracefully handle insufficient funds.  #203]
• Bug: When you fetch exactly 5 transaction, LW2.0 struggles with the pagination and displays nothing. [When fetching exactly 5 transactions, wallet details view renders no transactions. #218]
• 2x Resolution Icons for HiDPI displays. [2x Resolution Icons for HiDPI displays. #278]
• Be able to toggle between Fiat and MRT on send amount screen. [Be able to toggle between Fiat and MRT on send amount screen. #279]

=======================MERGE LINE=================================

• Investigate upgrading the Express Package. (We're almost ~3 years behind here.) [Spike upgrading to latest version of Express in MWS.  #201]

• Investigate upgrading async package. (We're almost ~3 years behind here.) [[MWS] Spike upgrading to latest version of Async. #202]

• Improve the usability of spending unconfirmed inputs. [LW should gracefully handle insufficient funds.  #203]

• Requests to /addresses/ and /wallets/ are blocked until getNotifications returns. [Requests are somehow blocked or delayed by getNotifications.  #204]

• Display recent transactions on the Wallets View (Home) [Show recent transactions on the Wallets View (Home) #205]

• Modernize easySend functionality. [Modernize EasySend  #210]

• Consider optimal way to format numbers on the wallet details page. [Improve formatting of amounts throughout LW. #211]

• Enhance the usability around coinbase rewards and spending them. [Enhance the usability of receiving and sending coinbase rewards.  #215]

• Enhance the usability and clarity around balances, especially just after spending Merit. [Enhance usability and flow around available balances.  #216]

• Bug: GetTxHistory doesn't work if you haven't actually refreshed the status. [GetTxHistory does not properly load history when wallet does not have a status.  #217]

• Show the "balance details" modal on the walletDetails screen. [Show the "balance details" modal on the walletDetails screen. #280]

• Better caching of UTXOs and inputs by address. [Better caching of UTXOs and Balances by Address #221]

• Queue requests to insight-API. [Queue requests to Insight-API. #220]

• Type the ambiguous 'wallets' properly throughout the application. (Should almost always be MeritWalletClient type.) [Ensure that we type all MWC instances in LW as MeritWalletClient #222]

• It appears that Ionic events are broadcast more than once. If this is the case, fix. [Ionic Events are broadcasted/received more than once.  #223]

DONE:

• Stop calling v1 notifications hundreds of times in quick succession.
• Sending Merit should work all the way through without promise chain errors.
• Re-write MWC in Typescript.
• Modernize Wallets View and associated services.
• Modernize Transactions View and associated services.
• Modernize Settings Views and associated services.
• Modernize Onboarding Views and associated services.
• Re-write core services to be promise-based (using bluebird promises.)
• Flatten dependencies between lightwallet, mwc, and bitcore-lib.
• Make the total payload of the application much smaller.
• Make the initial startup time much faster.
• Preliminary segwit support in LW stack (bitcore lib, primarily)

[adilwali]

After spending some time thinking on it, I think that this is generally the structural direction we want to head in.

I wasn't as thoughtful as I should have been originally about the Ionic approach, and how it is tied to the notion of pages. Pages, by design, are different than components. They have their own notion of hierarchy, etc.

This Issue over at Ionic sheds a little light on the topic: ionic-team/ionic-framework#6847

It sounds like they are heading in the direction of views over pages. So I tried to keep that in mind here.

The biggest open question on my mind is how to handle the primary navigation views. (The tabs: Send, Receive, Community, etc.) In order to get the modernization refactor done quickly without introducting too much risk, we can keep all these pages grouped (as they are today), perhaps with a more semantic name.

Some ideas that come to mind are:

• primary
• primary-actions
• transact

Of the above, I like transact the best, since it most closely describes what the primary actions allow you to do. The only exception might be the community tab, but if use the abstract notion of a transaction, then it's not crazy to think of a invitation as a transaction.

[adilwali]

Another important approach thing to think about is how much has been (over)loaded into the profile service. Going forward, we should strive to separate out thematically relevant functionality into more moderately-sized modules (including services).

At a high-level, I could see something like:

app/
├── core/
│   ├── profile.service.ts 
│   ├── wallet.service.ts
│   ├── keys.service.ts
├── lib/
│   ├──bwc.js

[adilwali]

Phew. Now you can click through the tourFlow with the new structure. And BWC makes a call to BWS when you attempt to unlock the wallet.

I want to clarify one thing as of this point:
It may seem contrived to create this level of modularity in a series of modules that are tightly-coupled.

So, the question is, why do it?

The answer is: we want to etch a blueprint of the architecture we desire in the code as of now. Yes, many components are still tightly coupled, so we do not get many of the benefits of lazy-loading. But, now that we have a framework, folder-structure, and a stylistic (folder-by-feature) approach in place, we can start refactoring in that direction.

So, in short, it'll get a bit worse before it gets better. But it will get better.

[adilwali]

Phew. As of now, this branch now has working transactions and eventing. It also has the bluebird types, and MeritWalletClient is typed in most places throughout the app to gain the true power of TypeScript.