Allow extra signup params from account

For the feature/invite-codes in leap_web, we need to be able to pass an
extra parameter (the invite code) from the signup form to the server.
This approach allows the consumer of SRP to specify a custom
implementation of Account that returns arbitrary `loginParams`, and
Session will pass them on so that they become part of the XHR.

- Split session.signup into signup and update to restrict extra params
  to signup only

1 files changed, 14 insertions, 1 deletions

diff --git a/src/srp_session.js b/src/srp_session.js
index bdff9c4..88f19d5 100644
--- a/src/srp_session.js
+++ b/src/srp_session.js
@@ -22,7 +22,7 @@ srp.Session = function(account, calculate) {
     return A;
   };
 
-  this.signup = function() {
+  this.update = function() {
     var salt = calculate.randomSalt();
     var x = calculate.X(account.login(), account.password(), salt);
     return {
@@ -30,6 +30,19 @@ srp.Session = function(account, calculate) {
       password_salt: salt,
       password_verifier: calculate.V(x)
     };
+  }
+
+  this.signup = function() {
+    var loginParams = this.update();
+
+    if (account.loginParams) {
+      var extraParams = account.loginParams();
+      for (var attr in extraParams) {
+        loginParams[attr] = extraParams[attr];
+      }
+    }
+
+    return loginParams;
   };
 
   this.handshake = function() {