script.js

// nav bar

$(document).ready(function(){
  $(window).scroll(function(){
  	var scroll = $(window).scrollTop();
	  if (scroll > 10) {
	    $(".navbar").css("background" , "rgba(43, 38, 38)");
	  }

	  else{
		  $(".navbar").css("background" , "rgba(43, 38, 38,0.5)");  	
	  }
  })
})


// Text section

const resolver = {
    resolve: function resolve(options, callback) {
      // The string to resolve
      const resolveString = options.resolveString || options.element.getAttribute('data-target-resolver');
      const combinedOptions = Object.assign({}, options, {resolveString: resolveString});
      
      function getRandomInteger(min, max) {
        return Math.floor(Math.random() * (max - min + 1)) + min;
      };
      
      function randomCharacter(characters) {
        return characters[getRandomInteger(0, characters.length - 1)];
      };
      
      function doRandomiserEffect(options, callback) {
        const characters = options.characters;
        const timeout = options.timeout;
        const element = options.element;
        const partialString = options.partialString;
  
        let iterations = options.iterations;
  
        setTimeout(() => {
          if (iterations >= 0) {
            const nextOptions = Object.assign({}, options, {iterations: iterations - 1});
  
            // Ensures partialString without the random character as the final state.
            if (iterations === 0) {
              element.textContent = partialString;
            } else {
              // Replaces the last character of partialString with a random character
              element.textContent = partialString.substring(0, partialString.length - 1) + randomCharacter(characters);
            }
  
            doRandomiserEffect(nextOptions, callback)
          } else if (typeof callback === "function") {
            callback(); 
          }
        }, options.timeout);
      };
      
      function doResolverEffect(options, callback) {
        const resolveString = options.resolveString;
        const characters = options.characters;
        const offset = options.offset;
        const partialString = resolveString.substring(0, offset);
        const combinedOptions = Object.assign({}, options, {partialString: partialString});
  
        doRandomiserEffect(combinedOptions, () => {
          const nextOptions = Object.assign({}, options, {offset: offset + 1});
  
          if (offset <= resolveString.length) {
            doResolverEffect(nextOptions, callback);
          } else if (typeof callback === "function") {
            callback();
          }
        });
      };
  
      doResolverEffect(combinedOptions, callback);
    } 
  }
  
  /* Some GLaDOS quotes from Portal 2 chapter 9: The Part Where He Kills You
   * Source: http://theportalwiki.com/wiki/GLaDOS_voice_lines#Chapter_9:_The_Part_Where_He_Kills_You
   */
  const strings = [
    'Thats one small step for a man, one giant leap for mankind.',
    'Discover the force of the skies O Men: once recognised it can be put to use.',
    'Across the sea of space, the stars are other suns.',
    'The history of astronomy is a history of receding horizons.',
    'There can be no centre in infinity.',
    'Curiosity is the essence of our existence.',
    'We are limited only by our imagination and our will to act.',
    '......'
  ];
  
  let counter = 0;
  
  const options = {
    // Initial position
    offset: 0,
    // Timeout between each random character
    timeout: 5,
    // Number of random characters to show
    iterations: 10,
    // Random characters to pick from
    characters: ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'x', 'y', 'x', '#', '%', '&', '-', '+', '_', '?', '/', '\\', '='],
    // String to resolve
    resolveString: strings[counter],
    // The element
    element: document.querySelector('[data-target-resolver]')
  }
  
  // Callback function when resolve completes
  function callback() {
    setTimeout(() => {
      counter ++;
      
      if (counter >= strings.length) {
        counter = 0;
      }
      
      let nextOptions = Object.assign({}, options, {resolveString: strings[counter]});
      resolver.resolve(nextOptions, callback);
    }, 1000);
  }
  
  resolver.resolve(options, callback);