Run results for: insertAdjacentHTML vs appendChild vs append vs insertAdjacentElement vs innerHTML repeat 1000

Test name	Executions per second
✓ innerHTML	301 Ops/sec
insertAdjacentHTML	239 Ops/sec
appendChild	121 Ops/sec
insertAdjacentElement	119 Ops/sec
append	103 Ops/sec

insertAdjacentHTML

const box = document.createElement('div');
let html = '';
for (let i = 0; i < repeat; i++)
  html += '<div class="a b"><div>Test</div></div>';
box.insertAdjacentHTML('beforeend', html);

appendChild

const box = document.createElement('div');
const els = [];
for (let i = 0; i < repeat; i++) {
  const div2 = document.createElement('div');
  div2.innerText = 'Test';
  const div1 = document.createElement('div');
  div1.className = 'a b';
  div1.appendChild(div2);
  els.push(div1);
}
els.forEach(el => box.appendChild(el));

append

const box = document.createElement('div');
const els = [];
for (let i = 0; i < repeat; i++) {
  const div2 = document.createElement('div');
  div2.innerText = 'Test';
  const div1 = document.createElement('div');
  div1.className = 'a b';
  div1.append(div2);
  els.push(div1);
}
box.append(...els);

insertAdjacentElement

const box = document.createElement('div');
const els = [];
for (let i = 0; i < repeat; i++) {
  const div2 = document.createElement('div');
  div2.innerText = 'Test';
  const div1 = document.createElement('div');
  div1.className = 'a b';
  div1.insertAdjacentElement('beforeend', div2);
  els.push(div1);
}
els.forEach(el => box.insertAdjacentElement('beforeend', el));

innerHTML

const box = document.createElement('div');
let html = '';
for (let i = 0; i < repeat; i++)
  html += '<div class="a b"><div>Test</div></div>';
box.innerHTML += html;