perf(*): Make AccountStore / ContactRankingStore less noisy

src/flux/models/category.coffee

@@ -1,6 +1,7 @@
 _ = require 'underscore'
 Model = require './model'
 Attributes = require '../attributes'
+AccountStore = null
 
 # We look for a few standard categories and display them in the Mailboxes
 # portion of the left sidebar. Note that these may not all be present on
@@ -97,7 +98,7 @@ class Category extends Model
     @
 
   displayType: =>
-    AccountStore = require '../stores/account-store'
+    AccountStore ?= require '../stores/account-store'
     if AccountStore.accountForId(@accountId).usesLabels()
       return 'label'
     else

src/flux/stores/account-store.coffee

@@ -83,7 +83,7 @@ class AccountStore extends NylasStore
     return unless NylasEnv.isMainWindow()
     idx = _.findIndex @_accounts, (a) -> a.id is id
     account = @_accounts[idx]
-    return if !account
+    return if !account or _.isEqual(account, updated)
     account = _.extend(account, updated)
     @_caches = {}
     @_accounts[idx] = account

src/flux/stores/contact-ranking-store.coffee

@@ -8,16 +8,29 @@ class ContactRankingStore extends NylasStore
   constructor: ->
     @_values = {}
     @_valuesAllAccounts = null
-    @_disposables = []
+    @_disposables = {}
     @listenTo AccountStore, @_onAccountsChanged
     @_registerObservables(AccountStore.accounts())
 
   _registerObservables: (accounts) =>
-    @_disposables.forEach (disp) -> disp.dispose()
-    @_disposables = accounts.map ({accountId}) =>
-      query = DatabaseStore.findJSONBlob("ContactRankingsFor#{accountId}")
-      return Rx.Observable.fromQuery(query)
-        .subscribe @_onRankingsChanged.bind(@, accountId)
+    nextDisposables = {}
+
+    # Create new observables, reusing existing ones when possible
+    # (so they don't trigger with initial state unnecesarily)
+    for acct in accounts
+      if @_disposables[acct.id]
+        nextDisposables[acct.id] = @_disposables[acct.id]
+        delete @_disposables[acct.id]
+      else
+        query = DatabaseStore.findJSONBlob("ContactRankingsFor#{acct.id}")
+        callback = @_onRankingsChanged.bind(@, acct.id)
+        nextDisposables[acct.id] = Rx.Observable.fromQuery(query).subscribe(callback)
+
+    # Remove unused observables in the old set
+    for key, disposable of @_disposables
+      disposable.dispose()
+
+    @_disposables = nextDisposables
 
   _onRankingsChanged: (accountId, json) =>
     @_values[accountId] = if json then json.value else null