runtimeterror/assets/js/typo.js

/*

Typo, a more natural web typing thing

https://neatnik.net/typo
https://github.com/neatnik/typo

Copyright (c) 2021 Neatnik LLC

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

*/

function num_between(min, max) {
  return Math.floor(Math.random() * (max- min + 1) + min);
}

function chance(val) {
  if(num_between(0, 100) < val) return true;
  else return false;
}

function sleep(ms) {
  return new Promise(resolve => setTimeout(resolve, ms));
}

var typos = {
  q:['w','a'],
  w:['q','r','s'],
  e:['w','d','r'],
  r:['e','f','t'],
  t:['r','g','y'],
  y:['t','h','u'],
  u:['y','j','i'],
  i:['u','k','o'],
  o:['i','l','p'],
  p:['o',';','['],
  a:['q','s','z'],
  s:['w','a','x','d'],
  d:['e','s','c','f'],
  f:['r','d','v','g'],
  g:['t','f','b','h'],
  h:['y','g','n','j'],
  j:['u','h','m','k'],
  k:['i','j',',','l'],
  l:['o','k','.',';'],
  z:['a','x'],
  x:['z','s','c'],
  c:['x','d','v'],
  v:['c','f','b'],
  b:['v','g','n'],
  n:['b','h','m'],
  m:['n','j',','],
}

async function typo(element, text) {
  var buffer = '';
  var typo_active = false;
  var typing_typos = (element.dataset.typoChance) ? element.dataset.typoChance : 10;
  var typing_speed = (element.dataset.typingDelay) ? element.dataset.typingDelay : 50;
  var typing_jitter = (element.dataset.typingJitter) ? element.dataset.typingJitter : 15;

  for (var i = 0; i < text.length; i++) {
    // Get the letter that we're supposed to type
    letter = text.charAt(i);

    // Trigger a typo
    if(chance(typing_typos) && typo_active === false && i > 1 && i < text.length - 3) {
      if(typeof typos[letter] !== 'undefined') {
        // Swap the letter with a random typo
        typo = typos[letter][Math.floor(Math.random() * typos[letter].length)];

        // Append the letter to the buffer
        buffer = buffer + typo;

        // Write the buffer
        element.innerHTML = buffer;

        typo_active = true;
        var seed = num_between(2,5);  // Reduced max seed to ensure correction
        realization_delay = seed;
        realization_delay_counter = seed;
      }
    }

    // Append the letter to the buffer
    buffer = buffer + letter;

    // Write the buffer
    element.innerHTML = buffer;

    // Typical typing speed
    var speed_lower = parseFloat(typing_speed) - parseInt(typing_jitter);
    var speed_upper = parseFloat(typing_speed) + parseInt(typing_jitter);

    delay = num_between(speed_lower,speed_upper);

    // Chance of longer delay though
    if(chance(5)) delay = num_between(100, 200);
    await sleep(delay);

    if(typo_active) {
      realization_delay_counter--;

      if(realization_delay_counter == 0) {
        for (var k = 0; k < seed+1; k++) {
          // Pause at realization of typo
          await sleep(typing_jitter);

          // Rewind the buffer!
          buffer = buffer.substring(0, buffer.length - 1);

          // Write rewound buffer
          element.innerHTML = buffer;

          // Brief pause before continuing
          await sleep(30);
        }

        typo_active = false;

        // Add the letters back
        i = i - seed;
        await sleep(100);
      }
    }
  }

  // Ensure any remaining typo is corrected
  if(typo_active) {
    await sleep(typing_jitter * 2);
    for (var k = 0; k < seed+1; k++) {
      buffer = buffer.substring(0, buffer.length - 1);
      element.innerHTML = buffer;
      await sleep(30);
    }
    for (var k = 0; k < seed; k++) {
      buffer += text.charAt(text.length - seed + k);
      element.innerHTML = buffer;
      await sleep(typing_speed);
    }
  }

  return new Promise(resolve => setTimeout(resolve, 1));
}

document.addEventListener('DOMContentLoaded', function() {
  var element = document.getElementById('tagline');
  var text = element.innerHTML;
  typo(element, text);
});