2 files changed, 25 insertions, 2 deletions

diff --git a/api/team.go b/api/team.go
index 15e4e2c17..7265b1d07 100644
--- a/api/team.go
+++ b/api/team.go
@@ -456,6 +456,15 @@ func inviteMembers(c *Context, w http.ResponseWriter, r *http.Request) {
 		user = result.Data.(*model.User)
 	}
 
+	var invNum int64 = 0
+	for _, invite := range invites.Invites {
+		if result := <-Srv.Store.User().GetByEmail(c.Session.TeamId, invite["email"]); result.Err == nil || result.Err.Message != "We couldn't find the existing account" {
+			c.Err = model.NewAppError("invite_members", "This person is already on your team", strconv.FormatInt(invNum, 10))
+			return
+		}
+		invNum++;
+	}
+
 	ia := make([]string, len(invites.Invites))
 	for _, invite := range invites.Invites {
 		ia = append(ia, invite["email"])
diff --git a/web/react/components/invite_member_modal.jsx b/web/react/components/invite_member_modal.jsx
index d1672126d..bfcbfc94f 100644
--- a/web/react/components/invite_member_modal.jsx
+++ b/web/react/components/invite_member_modal.jsx
@@ -43,6 +43,7 @@ module.exports = React.createClass({
         var first_name_errors = this.state.first_name_errors;
         var last_name_errors = this.state.last_name_errors;
         var valid = true;
+        var profiles = UserStore.getProfiles();
 
         for (var i = 0; i < count; i++) {
             var index = invite_ids[i];
@@ -52,6 +53,13 @@ module.exports = React.createClass({
                 email_errors[index] = "Please enter a valid email address";
                 valid = false;
             } else {
+                for (var email in profiles) {
+                    if (email === invite.email) {
+                        email_errors[index] = "This person is already on your team";
+                        valid = false;
+                    }
+                }
+
                 email_errors[index] = "";
             }
 
@@ -89,7 +97,12 @@ module.exports = React.createClass({
                 $(this.refs.modal.getDOMNode()).modal('hide');
             }.bind(this),
             function(err) {
-                this.setState({ server_error: err });
+                if (err.message === "This person is already on your team") {
+                    email_errors[err.detailed_error] = err.message;
+                    this.setState({ email_errors: email_errors });
+                }
+                else
+                    this.setState({ server_error: err.message});
             }.bind(this)
         );
 
@@ -138,7 +151,8 @@ module.exports = React.createClass({
             id_count: 0,
             email_errors: {},
             first_name_errors: {},
-            last_name_errors: {}
+            last_name_errors: {},
+            server_errors: {}
         };
     },
     render: function() {