https://github.com/mmiller42/maybe-promise-factory
The maybePromiseFactory normalizes synchronous values and asynchronous values by always returning a Promise.
https://github.com/mmiller42/maybe-promise-factory
Last synced: 3 months ago
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The maybePromiseFactory normalizes synchronous values and asynchronous values by always returning a Promise.
- Host: GitHub
- URL: https://github.com/mmiller42/maybe-promise-factory
- Owner: mmiller42
- License: other
- Created: 2015-05-20T23:01:26.000Z (about 10 years ago)
- Default Branch: master
- Last Pushed: 2016-05-12T02:05:54.000Z (about 9 years ago)
- Last Synced: 2025-03-11T01:09:58.602Z (3 months ago)
- Language: JavaScript
- Homepage:
- Size: 7.81 KB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# maybe-promise-factory
The maybePromiseFactory normalizes synchronous values and asynchronous values by always returning a Promise.
* The factory uses the ES6 Promise implementation by default but can use other Promise implementations.
* The returned maybePromise function accepts an argument and converts it to a promise if it is another type of value.
* If it is passed a function, it invokes it and applies the same rules to the result of the function to promisify it.
* If the invoked function throws an exception, it is caught and a rejected Promise is returned.
## Installation
Install with `npm install maybe-promise-factory`.
## Usage Examples
```js
const maybePromise = require('maybe-promise-factory')();
// If passed a non-Promise value, coerces it into an immediately-resolved Promise.
maybePromise(42).then(res => console.log(res)); // 42
// If passed a Promise, simply returns the Promise.
maybePromise(new Promise(resolve => resolve(42))).then(res => console.log(res)); // 42
// If passed a function, invokes the function. If the function returns a non-Promise value,
// coerces the result into an immediately-resolved Promise.
maybePromise(syncSum.bind(null, 1, 2)).then(res => console.log(res)); // 3
// If passed a function, invokes the function. Thrown exceptions are caught and the Promise
// is rejected with the exception.
maybePromise(syncSum.bind(null, 1, 'x').catch(err => console.error(err)); // TypeError
function syncSum (a, b) {
if (typeof a === 'number' && typeof b === 'number') {
return a + b;
} else {
throw new TypeError('Invaild arguments passed to syncSum');
}
}
// If passed a function, invokes the function. If the function returns a Promise, simply
// returns the Promise.
maybePromise(asyncSum.bind(null, 1, 2)).then(res => console.log(res)); // 3
maybePromise(asyncSum.bind(null, 1, 'x').catch(err => console.error(err)); // TypeError
function asyncSum (a, b) {
return new Promise((resolve, reject) => {
if (typeof a === 'number' && typeof b === 'number') {
resolve(a + b);
} else {
reject(new TypeError('Invalid arguments passed to asyncSum'));
}
});
}
// Using other Promise implementations
const Bluebird = require('bluebird');
const maybePromise = require('maybe-promise-factory')(Bluebird);
```
## Testing
Tests are written with Mocha and Should. They can be run with `npm test`.