> For the complete documentation index, see [llms.txt](https://javascript-1.gitbook.io/javascript/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://javascript-1.gitbook.io/javascript/promises-execution.md).

# Promises Execution

Three different ways to execute promises.

1. Parallel - all at a time
2. Sequence - one by one
3. Race - who comes first

```javascript
// Basic Data
const promisify = (item, delay) =>
  new Promise((resolve) =>
    setTimeout(() =>
      resolve(item), delay));

const a = () => promisify('a', 100);
const b = () => promisify('b', 5000);
const c = () => promisify('c', 3000);
```

#### Parallel:

```javascript
async function parallel() {
  const promises = [a(), b(), c()];
  const [output1, output2, output3] = await Promise.all(promises);
  return `prallel is done: ${output1} ${output2} ${output3}`
}
parallel().then(console.log); // prallel is done: a b c
```

#### Sequence:

```javascript
async function sequence() {
  const output1 = await a();
  const output2 = await b();
  const output3 = await c();
  return `sequence is done ${output1} ${output2} ${output3}`
}
sequence().then(console.log); // sequence is done: a b c
```

#### Race:

```javascript
async function race() {
  const promises = [a(), b(), c()];
  const output1 = await Promise.race(promises);
  return `race is done: ${output1}`;
}
race().then(console.log) // race is done: a
```