Waits for predicate to be truthy and resolves a Promise
$ npm install async-wait-until
const waitUntil = require('async-wait-until');
const timeOfStart = Date.now();
// Wait for some async operation to end
waitUntil(() => {
const timePassed = Date.now() - timeOfStart;
return (timePassed < 500)
&& (timePassed % 2 === 0) // Some random stuff
? true
: throw new Error('Async operation failed');
}, 600)
.then((result) => {
// Here are the operations to be done after predicate
console.log('Async operation succeeded, predicate result = ', result);
})
.catch((error) => {
// Here are the operations to be done if predicate didn't succeed in the timeout
console.log('Async operation failed: ', error);
});
The library is async/await compatible because it uses Promises/A+, so the example above could be rewritten:
const waitUntil = require('async-wait-until');
const timeOfStart = Date.now();
// Wait for some async operation to end
try {
const result = await waitUntil(() => {
const timePassed = Date.now() - timeOfStart;
return (timePassed < 500)
&& (timePassed % 2 === 0) // Some random stuff
? true
: throw new Error('Async operation failed');
}, 600)
// Here are the operations to be done after predicate
console.log('Async operation succeeded, predicate result = ', result);
} catch (error) {
// Here are the operations to be done if predicate didn't succeed in the timeout
console.log('Async operation failed: ', error);
}
/**
* Waits for predicate to be truthy and resolves a Promise
*
* @param predicate Function Predicate that checks the condition
* @param timeout Number Maximum wait interval, optional, 5000ms by default
* @param interval Number Wait interval, optional, 50ms by default
* @return Promise Promise to return a callback result
*/
function waitUntil(
predicate: Function,
timeout: Number = 5000,
interval: Number = 50
): Promise;
Library has 100% test coverage:
$ npm run test:coverage
> async-wait-until@1.1.4 test:coverage ~/projects/waitUntil
> NODE_ENV=test jest --coverage --no-cache --config .jestrc
PASS test/waitUntil.js
waitUntil
✓ Should apply callback and resolve result (219ms)
✓ Should apply callback and resolve non-boolean result (209ms)
✓ Should reject with timeout error if timed out (108ms)
✓ Should not do double reject on timeout (205ms)
✓ Should not do double reject on timeout if error in predicate (213ms)
✓ Should reject result if error in predicate (55ms)
--------------|----------|----------|----------|----------|----------------|
File | % Stmts | % Branch | % Funcs | % Lines |Uncovered Lines |
--------------|----------|----------|----------|----------|----------------|
All files | 100 | 100 | 100 | 100 | |
waitUntil.js | 100 | 100 | 100 | 100 | |
--------------|----------|----------|----------|----------|----------------|
Test Suites: 1 passed, 1 total
Tests: 6 passed, 6 total
Snapshots: 0 total
Time: 1.984s
Ran all test suites.
Library is 100% compatible with airbnb-base for ES5.
Library has the following commands available:
-
Run the tests:
$ npm test
-
Run the tests and display test coverage:
$ npm run test:coverage
-
Run the linter:
$ npm run lint
No building required, library is implemented with ES5 for better compatibility and shipped as is.
Library is shipped "as is" under MIT License.
Feel free to contribute but don't forget to test everything properly.