How to work properly with promises in JavaScript after closing the browser?

Question

I am using firebase or pouchsb / couchdb + vuejs / quasar. My architecture does not imply a server layer as such.

There is a task of the following nature. Let's say that at 14:00 the user creates an order that must be executed at 15:00. What if the browser is closed and then reopened at 14:58?

How to make a promise to be fulfilled after closing and reopening the browser?

Answer 1

You can't. When the browser is closed (or the page existed) the JS environment goes away and all promises disappear. You need to take a different approach.

A typical approach would be to store the data about the order in (for example) localStorage and then:

• Delete it when the order is executed
• Read it when the page is loaded and:
  • put pending orders back on the queue
  • handle out-of-date orders however you like (e.g. display an error or submit them late)