• Empleos
  • Sobre nosotros
  • profesionales
    • Inicio
    • Empleos
    • Cursos y retos
    • Preguntas
    • Profesores
  • empresas
    • Inicio
    • Publicar vacante
    • Nuestro proceso
    • Precios
    • Pruebas Online
    • Nómina
    • Blog
    • Comercial
    • Calculadora de salario

0

272
Vistas
What is the impact of await and .then() on the stack?

I'm having trouble understanding the control flow in the following code. The await in the await setTimeout(() => console.log("Await timeout executed"), 0) line seems to yield control back to the main thread, causing 'I am in main()' to be logged to the console. If I remove the await, the order of the output changes -- "The function is done executing" now comes before "I am in the main thread". I understand the rest of the code but don't get what the stack looks like here. Do await and .then() always return control to the caller? If so, how does the program know to put those functions back on the stack? Thanks.

async function test () {
  console.log("Execution starting");

  setTimeout(() => console.log("Timeout executed"), 0);

  await setTimeout(() => console.log("Await timeout executed"), 0);

  Promise.resolve(5).then(function log() { console.log("Hello from the first promise!") })

  console.log('The function is done executing')
}

test()
console.log('I am in main()')

//Execution starting
//I am in main()
//The function is done executing
//Hello from the first promise!
//Timeout executed
//Await timeout executed
almost 3 years ago · Juan Pablo Isaza
Responde la pregunta
Encuentra empleos remotos

¡Descubre la nueva forma de encontrar empleo!

Top de empleos
Top categorías de empleo
Empresas
Publicar vacante Precios Nuestro proceso Comercial
Legal
Términos y condiciones Política de privacidad
© 2025 PeakU Inc. All Rights Reserved.

Andres GPT

Recomiéndame algunas ofertas
Necesito ayuda