submittedUser is undefined every once in a while

[tjeerdytsma]

I found that every once in a while the program crashes on a undefined submittedUser in submittedUsers.

I used the following solution

function checkUsersValid(goodUsers) {
  return function allUsersValid(submittedUsers) {
    const result = submittedUsers.every(function (submittedUser) {
      const result = goodUsers.some(function(goodUser) {
        return submittedUser.id === goodUser.id;
      });
      return result;
    });
    return result;
  };
}

module.exports = checkUsersValid

which resulted in this error

/Users/tjeerd/Development/nodeschool/program.js:11
        return submittedUser.id === goodUser.id;
                            ^

TypeError: Cannot read property 'id' of undefined
    at /Users/tjeerd/Development/nodeschool/program.js:11:29
    at Array.some (<anonymous>)
    at /Users/tjeerd/Development/nodeschool/program.js:8:32
    at Array.every (<anonymous>)
    at allUsersValid (/Users/tjeerd/Development/nodeschool/program.js:6:35)
    at /usr/local/lib/node_modules/functional-javascript-workshop/exercises/basic_every_some/exercise.js:35:5
    at Array.forEach (<anonymous>)
    at /usr/local/lib/node_modules/functional-javascript-workshop/exercises/basic_every_some/exercise.js:34:9
    at obtainResult (/usr/local/lib/node_modules/functional-javascript-workshop/exercises/runner.js:100:21)
    at Exercise.<anonymous> (/usr/local/lib/node_modules/functional-javascript-workshop/exercises/runner.js:66:27)

Using node version v8.6.0 and functional-javascript-workshop@1.0.6