JavaScript How to process asynchronous functions in a loop sequentially asynchronous process callback

I am trying to change text so that they happen one at a time, almost in a consecutive looking way.

columns.forEach((x) => {
    setTimeout(() => {
        x.style.color="red"
    }, 2500)

})

However, this is just delaying them all from happening 2500ms and then after 2500ms, they all change at the same time.

Answer:1

Promises with async / await, make doing things like this looks so much more natural, and easy to follow / debug.

const columns = document.querySelectorAll("td");

const sleep = (ms) => new Promise(r => setTimeout(r, ms));

async function run() {
  for (const c of columns) {
    await sleep(2500);
    c.style.color = 'red';
  }
}

run();
td {
  border: 1px solid black;
  padding: 5px;
  margin: 3px;
}
<table>
  <tr>
    <td>1</td>
    <td>2</td>
    <td>3</td>
    <td>4</td>
    <td>5</td>
    <td>6</td>
    <td>7</td>
  </tr>
</table>
Answer:2

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