回答編集履歴

  window.addEventListener('DOMContentLoaded', ()=>{

  const data=localStorage.data?JSON.parse(localStorage.data):[];

  const add=document.querySelector('#add-text');

  const ul=document.querySelector('#list ul');

  ul.innerHTML="";

  data.map(x=>[

  Object.assign(document.createElement('input'),{type:'button',value:'del',className:'del'}),

  ].reduce((x,y)=>(x.appendChild(y),x),document.createElement('li'))).forEach(x=>ul.appendChild(x));

  }

  document.addEventListener('click',e=>{

  const t=e.target;

  if(t.closest('.del')){

  }

  if(t instanceof HTMLInputElement){

  localStorage.data=JSON.stringify(data);

  }

  });

  });

  <div id="list">

  <ul></ul>

  </div>