alexshelkov

var i1 = 0;

while (i1 < 3) {
  let i = i1; // 'i' is a block scoped variable, 
              // each code block have unique copy of it

  setTimeout(() => { // timeout callback
    console.log(i, i1);
  }, i * 1000);

alexshelkov

var i = 0;

while (i < 3) {
  setTimeout(() => { // timeout callback
    console.log(i);
  }, i * 1000);

  i++;
}

alexshelkov

var i; // 'i' was declared with functional scope,
       // so its declaration moved to the top of the file
for (i = 0; i < 3; i++) {
  setTimeout(() => { // timeout callback
    console.log(i);
  }, i * 1000);
}

alexshelkov

{ // start of the block scope

  // TODO: try uncomment
  // console.log(a);
  // hoisting works differently for blocks scope, and it will throw an error:
  // 'ReferenceError: Cannot access a before initialization'

  let a = 1; // 'a' defined and we can start to use it
             //  
  console.log(a);

alexshelkov

// file scope

var a; // declaration of 'a' moved on top of the file and split from assignment

console.log(a); // so here 'a' is undefined, but declared,
                // so it does not throw an error
a = 1; // now 'a' is assigned to 1
console.log(a);

function f1() { // f1 scope

alexshelkov

// file scope

console.log(a); // you may be surprised, but this works and logs undefined
                // this is because of the hoisting of definitions 
                // on top of the nearest function
var a = 1;
console.log(a);

function f1() { // f1 scope
  console.log(a); // this is ok -- functions have access to parent scope

alexshelkov

for (let i = 0; i < 3; i++) {
  setTimeout(() => {
    console.log(i);
  }, i * 1000);
}

alexshelkov

for (var i = 0; i < 3; i++) {
  setTimeout(() => {
    console.log(i);
  }, i * 1000);
}

alexshelkov

<?php
// somewhere in the module code


public function onBootstrap(EventInterface $event)
{
    /** @var \Zend\Mvc\MvcEvent $event  */
    $application = $event->getApplication();

    $application->getEventManager()->attach('dispatch', function(MvcEvent $event) use ($application) {

alexshelkov

$factory = new \Zend\InputFilter\Factory();
$i = $factory->createInputFilter(array(
    'password' => array(
        'name'       => 'password',
        'required'   => true,
        'validators' => array(
            array(
                'name' => 'not_empty',
            ),
            array(