wait-for-async

import waitFor from `wait-for-async`;

await waitFor({ interval, condition, times });

Wait for condition() to be true. Its value is checked every interval milliseconds, check no more than times intervals in total.

Whenever condition() becomes true, return true. If condition() never becomes true until times intervals passed, return false.

Parameters explained

interval

The intervals (in milliseconds) on how often to check condition()'s value.

Default value is 1000.

At least 1 interval will be waited before condition() is checked, even if condition() is true at the very beginning.

condition

condition() is a method which returns true or false.

Default value is () => true.

times

How many times in total to check condition()'s value before giving up.

Default value is Infinity.

This is the maximum times to check. Fewer times to check if condition()'s value becomes true sooner.

return value

true if condition() becomes true before giving up, otherwise return false.

Or simply put, condition()'s value will be returned.

Interesting use cases

Wait for file downloading

let downloaded = false;
await waitFor({ condition: () => downloaded, times: 60)

Wait for downloaded to become true (this variable should be updated by the file downloading code).

Check downloaded's value every second (interval's default value is 1000ms), and give up after 60 seconds(60 checks).

"Delay" the app for 3 seconds

await waitFor({ interval: 3000 });