interview2.js

// 1. Write a `until(condition, finalCallback)` function that calls the `condition` function until the result is truthy, then calls the final callback

function waitUntilUserLoggedIn() {
    until(function(callback) {
        ajax('/api/user', function(err, user) {
            if (err) {
                callback(err);
            } else {
                callback(null, user.is_logged_in ? true : false)
            }
        });
    }, function(err, result) {
        console.log('user is logged in!');
    });
}

// 2. Write a function that tests if a function is alphanumeric [0-9a-zA-Z] *without* using a regex, and returns true/false

// 3. Write a regex which matches the following lines:

var foo = 'bar';
let xy_z = '123';
const ab123 = "hello world";

// 4. Write a "once" function

function sayHello(person) {
    console.log('hello', person)
}

let sayHelloOnce = once(sayHello);

sayHelloOnce('jill');
sayHelloOnce('jill');
sayHelloOnce('jill');

// Should only log 'hello jill' a single time

// 5. You have an ajax function which takes a callback:

ajax('/foobar', function(err, result) {
  if (err) {
    // do something
  } else {
    // do something
  }
});

// Using ajax(), write a promiseAjax() function which calls ajax() and turns it into a promise, so I can do:

ajaxPromise('/foobar').then(function(result) {
  // do something
}).catch(function(err) {
  // do something
});

// 6. Write a function which finds the sum of all the numbers in a nested array, like [1, 2, 3, [ 5, 2, 4, [ 3 ], 4, [ 6, 4, 5, [ 1, 2 ] ] ] ]

// 7. Write a function to find all the prime numbers between 1 and 1000

// 8. Write a form with a text field and a button, and write some javascript to only allow the form to submit if the text field has a word with a number of letters divisible by 3

// 9. Write a text box which takes what you type and puts it onto the page as you type

// 10. Write a React component which does the same as #9