How To Check Whether Current User Belongs To A Certain Group Using JavaScript

Using JavaScript Client Object Model:

 

function isCurrentUserInGroup(groupName, functionUserInGroup, functionUserNotInGroup, functionGroupNotFound, functionOnError) {

    var ctx = new SP.ClientContext.get_current();

    //Get info of current user

    var currentUser = ctx.get_web().get_currentUser();

    ctx.load(currentUser, 'Id', 'LoginName');

    //Retrieve all site groups

    var groups = ctx.get_web().get_siteGroups();

    ctx.load(groups);

 

    ctx.executeQueryAsync(function (sender, args) {

        //See whether the group exists

        var groupFound = false;

        var groupEnumerator = groups.getEnumerator();

        while (groupEnumerator.moveNext() && !groupFound) {

            var group = groupEnumerator.get_current();

            if (group.get_title() == groupName) {

                //Found the group, now try to load users of this group

                groupFound = true;

                var users = group.get_users();

                ctx.load(users);

                ctx.executeQueryAsync(function (sender, args) {

                    //See whether the user exists

                    var userFound = false;

                    var userEnumerator = users.getEnumerator();

                    while (userEnumerator.moveNext() && !userFound) {

                        var user = userEnumerator.get_current();

                        if (user.get_id() == currentUser.get_id()) {

                            //User exists in the group

                            userFound = true;

 

                            if (functionUserInGroup != null)

                                functionUserInGroup();

                        }

                    }

 

                    //User doesn't exist in the group

                    if (!userFound && (functionUserNotInGroup != null))

                        functionUserNotInGroup();

 

                }, function (sender, args) {

                    if (functionOnError != null)

                        functionOnError(sender, args);

 

                });

            }

        }

 

        //Group doesn't exist

        if (!groupFound && (functionGroupNotFound != null))

            functionGroupNotFound();

 

    }, function (sender, args) {

        if (functionOnError != null)

            functionOnError(sender, args);

 

    })

 

}

 

// Sample usage 

ExecuteOrDelayUntilScriptLoaded(function () {

    isCurrentUserInGroup('Approvers',

                         function () {

                            alert('User is in the group.');

                         },

                         function () {

                            alert('User is NOT in the group.');

                         },

                         function () {

                             alert('Group does NOT exist.');

                         },

                         function (sender, args) {

                             alert('Request failed.' + args.get_message() + '\n' + args.get_stackTrace());

                         });

}, "sp.js");