Promise & Async Visualizer

Step through async execution to understand call stack, microtask queue, macrotask queue, and Web APIs

Examples:

Code

console.log('start')

setTimeout(() => {
  console.log('timeout')
}, 0)

Promise.resolve()
  .then(() => console.log('promise 1'))
  .then(() => console.log('promise 2'))

console.log('end')

Expected Output

startendpromise 1promise 2timeout

1 / 21

Speed:1200ms

Call Stack

Script starts executing. The global script frame is pushed onto the call stack.

Call Stack

Microtask Queue

Empty

Macrotask Queue

Empty

Web APIs

No active timers

Console Output

0 lines

No output yet