Duplicates finder

duplicates-finder.markdown

Duplicates finder

A Pen by Olivvv on CodePen.

License.

index.html

<script type="text/js-worker">
  const getRandomInt = (max) =>  Math.floor(Math.random() * (max + 1));
  const findDuplicates = (e) => {
    const ints = [], dupes = [], n = e.data;
    for(let i = 0; i <= n; i++){
      let randomInt = getRandomInt(n);
      if (ints.includes(randomInt) && !dupes.includes(randomInt)){
        dupes.push(randomInt);
      }
      ints.push(randomInt);
      if (i%100==0 || i==n){
         self.postMessage({i: i, dupes: dupes});
       } 
    }
  }    
  self.addEventListener('message', (e) => findDuplicates(e));
</script>
<input type="number" id="intsRange" step="1" min="1" max="5000000" value="1000000"/>
<button type="button" id="toggleStartStop">Start</button>
<div id="output"></div>

script.js

const findDuplicates = function(inputElement,outputElement) {
  let worker = undefined;

  const createWorker = () => {
    const blob = new Blob(
      Array.prototype.map.call(
        document.querySelectorAll('script[type="text\/js-worker"]'),
         (oScript) => oScript.textContent
      ),
      { type: 'text/javascript' }
    );
    return new Worker(window.URL.createObjectURL(blob));
  } 

   const startWorker = () => {
    if(worker === undefined){
      worker = createWorker();

      worker.addEventListener('message', (e) => {
        let out = `Processed ${e.data.i}. ${e.data.dupes.length} duplicates : ${e.data.dupes.join(' ')}`;
        outputElement.innerHTML = out;
      });

      worker.postMessage(inputElement.value);
    }   
  }

  const stopWorker = () =>{
    if (worker && worker.terminate){
       worker.terminate();
    }
    worker = undefined;
  }
  const isRunning = () => {
    return (worker) ? true: false;
  }
  return {startWorker,stopWorker, isRunning};
}

const fd = new findDuplicates(document.getElementById('intsRange'), document.getElementById('output'));
document.getElementById('toggleStartStop').addEventListener('click', (e) => {
  if (!fd.isRunning()){
    fd.startWorker();
    e.target.innerHTML='Stop';    
  } else {
    fd.stopWorker();
    e.target.innerHTML='Restart';       
  }
});