mergeRoles = function (srcEntityRoles, tgtEntityRoles) {
    const rolesMap = srcEntityRoles.reduce((map, role) => (map[role] = true, map), {});
    tgtEntityRoles.forEach(role => {
        if (!rolesMap[role]) {
            srcEntityRoles.push(role);
        }
    });
}
Helper function merge roles
@param {string []} srcEntityRoles contents of the current collection
@param {string []} tgtEntityRoles target entity roles collection to merge
@returns {void} nothing