If you can't explain it to a six-year old, you really don't understand it yoursel... ~ Albert Einstein
Well I tried to explain JavaScript closures to a 27 years old friend and completely failed.
Can anybody consider that I am 6 and strangely interested in that subject?
I'm a big fan of analogy and metaphor when explaining difficult concepts, so let me try my hand with a story.
Once upon a time, there was a princess...
function princess() {
She lived in a wonderful world full of adventures. She met her Prince Charming, rode around her world on a unicorn, battled dragons, encountered talking animals, and many other fantastical things.
var adventures = [];
function princeCharming() { /* ... */ }
var unicorn = { /* ... */ },
dragons = [ /* ... */ ],
squirrel = "Hello!";
/* ... */
But she would always have to return back to her dull world of chores and grown-ups.
return {
And she would often tell them of her latest amazing adventure as a princess.
story: function() {
return adventures[adventures.length - 1];
}
};
}
But all they would see is a little girl...
var littleGirl = princess();
...telling stories about magic and fantasy.
littleGirl.story();
And even though the grown-ups knew of real princesses, they would never believe in the unicorns or dragons because they could never see them. The grown-ups said that they only existed inside the little girl's imagination.
But we know the real truth; that the little girl with the princess inside...
...is really a princess with a little girl inside.