Add atom.getReleaseChannel

spec/atom-environment-spec.coffee

@@ -328,3 +328,18 @@ describe "AtomEnvironment", ->
       runs ->
         {releaseVersion} = updateAvailableHandler.mostRecentCall.args[0]
         expect(releaseVersion).toBe 'version'
+
+  describe "::getReleaseChannel()", ->
+    [version] = []
+    beforeEach ->
+      spyOn(atom, 'getVersion').andCallFake -> version
+
+    it "returns the correct channel based on the version number", ->
+      version = '1.5.6'
+      expect(atom.getReleaseChannel()).toBe 'stable'
+
+      version = '1.5.0-beta10'
+      expect(atom.getReleaseChannel()).toBe 'beta'
+
+      version = '1.7.0-dev-5340c91'
+      expect(atom.getReleaseChannel()).toBe 'dev'

src/atom-environment.coffee

@@ -417,6 +417,16 @@ class AtomEnvironment extends Model
   getVersion: ->
     @appVersion ?= @getLoadSettings().appVersion
 
+  # Returns the release channel as a {String}. Will return one of `'dev', 'beta', 'stable'`
+  getReleaseChannel: ->
+    version = @getVersion()
+    if version.indexOf('beta') > -1
+      'beta'
+    else if version.indexOf('dev') > -1
+      'dev'
+    else
+      'stable'
+
   # Public: Returns a {Boolean} that is `true` if the current version is an official release.
   isReleasedVersion: ->
     not /\w{7}/.test(@getVersion()) # Check if the release is a 7-character SHA prefix