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Customizing Konami JS

The default implementation of Konami JS will trigger a redirect to the URL passed in as a string whenever a visitor enters the Konami Code via a keyboard or gesture input.

You can customize the input sequences and response for more intersting easter eggs.

Customizing the sequence

If you'd like to change the input sequence to something other than the Konami Code you can specifiy this during initialization:

const easterEgg = new Konami("http://konamijs.mand.is/")
// Changes the keyboard pattern to the "ArrowUp" key 10 times
easterEgg.pattern = "38383838383838383838"
// Change the touch input pattern to a clockwise sequence: up, right, down, left
easterEgg.iphone.keys = ["UP", "RIGHT", "DOWN", "LEFT"]

Yes, touch events are still hard-coded to an iphone property as of v1.6.3. What can I say? I wrote this in 2009 and wasn't really thinking about the future.

Customizing the response

If you'd like the Konami JS easter egg to do something a little fancier than redirect your visitor to a different page, all you have to do is provide a callback function:

const easterEgg = new Konami(() => {
    const randomNumber = Math.round(Math.random()*100) + 2;
    alert(`Konami JS Lives! May its reign last another ${randomNumber} years`);
  }).

That's it!