Check if Current Users belongs to SP group using javascript Client Side Object Model

Question

I havent found a specific example of how to get the current user and then check if it belongs to a specific sharepoint group, as I havent found anything I cant provide a code,

help on the right direction is appreciated.

Answer 1

SharePoint 2013 CSOM

Prerequisites: compatible with SharePoint 2013 CSOM API only since SP.GroupCollection.getByName Method is not available in SharePoint 2010

How to check if current user belongs to SharePoint group via CSOM (JavaScript):

function IsCurrentUserMemberOfGroup(groupName, OnComplete) {

        var currentContext = new SP.ClientContext.get_current();
        var currentWeb = currentContext.get_web();

        var currentUser = currentContext.get_web().get_currentUser();
        currentContext.load(currentUser);

        var allGroups = currentWeb.get_siteGroups();
        currentContext.load(allGroups);

        var group = allGroups.getByName(groupName);
        currentContext.load(group);

        var groupUsers = group.get_users();
        currentContext.load(groupUsers);

        currentContext.executeQueryAsync(OnSuccess,OnFailure);

        function OnSuccess(sender, args) {
            var userInGroup = false;
            var groupUserEnumerator = groupUsers.getEnumerator();
            while (groupUserEnumerator.moveNext()) {
                var groupUser = groupUserEnumerator.get_current();
                if (groupUser.get_id() == currentUser.get_id()) {
                    userInGroup = true;
                    break;
                }
            }  
            OnComplete(userInGroup);
        }

        function OnFailure(sender, args) {
            OnComplete(false);
        }    
}

Usage

IsCurrentUserMemberOfGroup("Approvers", function (isCurrentUserInGroup) {
   if(isCurrentUserInGroup)
   {
      //...
   }
});

SharePoint 2010/2013 CSOM

function isUserMemberOfGroup(userId, groupId, success,error) {

     var ctx = SP.ClientContext.get_current(); 
     var allGroups = ctx.get_web().get_siteGroups();
     var group = allGroups.getById(groupId);
     ctx.load(group,'Users');

     ctx.executeQueryAsync(
        function(sender, args) {
            var userInGroup = findUserById(group.get_users(),userId);
            success(userInGroup);
       },
       error);    

       var findUserById = function(users,id){
           var found = false;
           var e =  group.get_users().getEnumerator();
           while (e.moveNext()) {
                var user = e.get_current();
                if (user.get_id() == id) {
                    found = true;
                    break;
                }
           } 
           return found; 
       };
}

Usage

var currentUserId = _spPageContextInfo.userId;
var groupId = 4;
isUserMemberOfGroup(currentUserId, groupId, 
      function (isCurrentUserInGroup) {
          if(isCurrentUserInGroup)
              console.log('Current user is a member of Owners group'); 
          else
              console.log('Current user is not a member of Owners group'); 
      },
      function(sender,args){
         console.log(args.get_message());
      });