Nodejs + Express - Cannot call method 'json' of undefined

Question

Nodejs + Express - Cannot call method 'json' of undefined

I'm working with Express, Hoganjs, Nodejs.

The code below keeps returning "500 TypeError: Cannot call method 'json' of undefined"

I figure there is something wrong with how I am calling getUsers, but I'm too much of a newbie to figure it out. None of the tutorials or forums I have referred to are helping as of yet.

exports.admin = function(req, res){
getUsers(function(error, res){
    res.render('admin', {
        title: 'Admin',
        userlist: res
    });
});
};



function getUsers(req, res) {
res.json([
    {username: "fake", permission: "admin" },
    {username: "fake2", permission: "user" }
])
}

exports.getUsers = getUsers;

node.js
express

Answer 1

OK, so your code snippet is not properly formatted and thus hard to read, but I think exports.admin is being called as an express route that takes req, res. So far so good. Then you call getUsers and pass it a callback, but getUsers doesn't take a callback, it takes req, res as well. It's unclear what you're trying to do, but something like this would be reasonable:

exports.admin = function(req, res) {
  loadUsers(function (error, users) {
    if (error) {
      return res.status(500).send(error);
    }
    res.render('admin', {
        title: 'Admin',
        userlist: users
    });
  }
};

exports.getUsers = function(req, res) {
    loadUsers(function (error, users) {
      if (error) {
        return res.status(500).send(error);
      }
      res.send(users);
    });
}

function loadUsers(callback) {
  process.nextTick(function () {
    callback(null, [
      {username: "fake", permission: "admin" },
      {username: "fake2", permission: "user" }]
    );
  });
}

An even better pattern would be to code loadUsers as middleware, FYI.