conditional when

lib/orpheus.coffee

@@ -372,12 +372,37 @@ class OrpheusAPI
 		# New or existing id
 		@id = id or @_generate_id()
 
-		# If and Unless are used to discard changes
-		# unless certain conditions are met
-		@only = @when = (fn) =>
-			fn.bind(this)()
+
+		# Runs the given `function` inside the model context. Optionally, if `only`
+		# or `when` receive the `condition` parameter it will only run the function
+		# conditionally.
+		# 
+		# Example usage:
+		#   
+		#   User('john')
+		#   .when ->
+		#     if the_sky_is_blue then @name.set('happy john')
+		#   .exec()
+		# 
+		#   User('john')
+		#   .when the_sky_is_blue, ->
+		#     @name.set('happy john')
+		#   .exec()
+		# 
+		# @param condition - {Mixed} if just one argument is passed, `condition` is
+		# assumed to be the function to run in the context of the model. If two arguments
+		# are passed, `condition` will be used to evaluate whether to run the function or
+		# not.
+		# @param fn - {Function} the function to run in the context of the model
+		# @return {this} for chaining
+		# 
+		@only = @when = (condition, fn = condition) =>
+			# Apply the function in the current context if the condition is truthy
+			fn.bind(this)() if condition
+			# Return `this` for chaining
 			return this
 
+
 		# Create functions for working with the relation set
 		# e.g. user(15).books.sadd('dune') will map to sadd
 		# orpheus:us:15:books dune.

test/orpheus.spec.coffee

@@ -308,7 +308,8 @@ describe 'Redis Commands', ->
 			.name.set('greg')
 			.exec()
 
-	it 'When', (done) ->
+	it '#When', (done) ->
+
 		class Player extends Orpheus
 			constructor: ->
 				@str 'name'
@@ -332,6 +333,34 @@ describe 'Redis Commands', ->
 						expect(res[0]).toBe 1
 						done()
 
+	it '#When with a condition as parameter', (done) ->
+
+		class User extends Orpheus
+			constructor: ->
+				@str 'name'
+
+		user = User.create()
+
+		user('test')
+		.name.set('hi')
+		.when true, -> @name.set('hello')
+		.exec ->
+			r.hget "#{PREFIX}:us:test", 'name', (_, res) ->
+				expect(res).toBe 'hello'
+
+				user('test2')
+				.name.set('hi')
+				.when false, ->
+					# I have no idea why, but moving this to the same line as the `when`
+					# will make the tests hang. BUT, it does work if the condition is true.
+					@name.set('hello')
+				.exec ->
+
+					r.hget "#{PREFIX}:us:test2", 'name', (_, res) ->
+						expect(res).toBe 'hi'
+
+						done()
+
 
 # Getting Stuff
 # ----------------------------------------------