A part of authorization is handled by injecting the user information. We need an endpoint that verifies whether a user is valid. To define /api/user/auth endpoint, follow these steps:

1.  Define the route endpoint inside server/api/index.js:

routerAuth.get('/users/auth', User.auth);

2. Define the auth function inside the user controller (server/api/user.js):

  auth: (req, res) => {
    if (!req.user) {
      handleFailure(res, { status: 401 });
    } else {
      Model.users
        .authUser(req.user.id)
        .then(user => handleSuccess(res, { user }))
        .catch(errors =>
  handleFailure(res, { errors, message: errors.message, status: 401 }),
        );
    }
  },

3. Define the authUser method inside server/models/user.js:

  Schema.statics.authUser = function(id) {
    return new Promise((resolve, reject) => {
      try {
        this.findOne({ _id: id })
          .then(user => {
            resolve(
              user.toJson({
                token: generateToken({ loginKey: user.loginKey }),
              }),
            );
          })
          .catch(error => reject(error));
      } catch (e) {
        reject(e);
      }
    });
  };