Q159982

by jun68ykt

HTML

<script src="https://getfirebug.com/firebug-lite-debug.js"></script>

JavaScript

const text = "あかあかあかあかなあかなまやははまや";
const results = new Set();

for (let i=0; i < text.length-2; ++ i) {  
  if (/^(.+)\1/.test(text.substr(i)))
    results.add(RegExp.$1);
}

console.log([...results]); // => ["あかあか", "かあ", "あか", "あかな", "は"]