Refactor to use password strength options

services/web/app/coffee/Features/Authentication/AuthenticationManager.coffee

@@ -28,13 +28,25 @@ module.exports = AuthenticationManager =
 			else
 				callback null, null
 
-	setUserPassword: (user_id, password, callback = (error) ->) ->
+	validateEmail: (email) ->
+		if !email?.length
+			return { message: 'email not set' }
+		return null
+
+	validatePassword: (password) ->
+		if !password?
+			return { message: 'password not set' }
 		if (Settings.passwordStrengthOptions?.length?.max? and
 				Settings.passwordStrengthOptions?.length?.max < password.length)
-			return callback("password is too long")
+			return { message: 'password is too short' }
 		if (Settings.passwordStrengthOptions?.length?.min? and
 				Settings.passwordStrengthOptions?.length?.min > password.length)
-			return callback("password is too short")
+			return { message: "password is too short" }
+		return null
+
+	setUserPassword: (user_id, password, callback = (error) ->) ->
+		validation = validatePassword(password)
+		return callback(validation.message) if validation?
 
 		bcrypt.genSalt BCRYPT_ROUNDS, (error, salt) ->
 			return callback(error) if error?

services/web/app/coffee/Features/User/UserRegistrationHandler.coffee

@@ -13,20 +13,11 @@ settings = require "settings-sharelatex"
 EmailHelper = require("../Helpers/EmailHelper")
 
 module.exports = UserRegistrationHandler =
-	hasZeroLengths : (props) ->
-		hasZeroLength = false
-		props.forEach (prop) ->
-			if prop.length == 0
-				hasZeroLength = true
-		return hasZeroLength
-
-	isTooShort: (prop, length) ->
-		return prop.length < length
-
 	_registrationRequestIsValid : (body, callback)->
 		email = EmailHelper.parseEmail(body.email) or ''
-		password = body.password
-		if @hasZeroLengths([password, email]) or @isTooShort(password, 6)
+		invalidEmail = AuthenticationManager.validateEmail(email)
+		invalidPassword = AuthenticationManager.validatePassword(body.password)
+		if invalidEmail? or invalidPassword?
 			return false
 		else
 			return true