Caching for asynchronous functions
- store key / value;
- store key, options / value (for example, for one url but for different methods);
- store promises;
- do not launch a promise for execution if there is already an unfulfilled promise for this key in the storage, the answer will be general;
- works with canceled promises;
Simply download and include with a script tag, Cache will be registered as a global variable.
<script src="../lib/cache.global.js"></script>
<script>
var cache = new Cache();
cache.add('test', 'value');
console.log(cache.match('test')); // 'value'
var makeRequest = function () {
return request('url', { method: 'GET' });
};
cache.add('promise-test', makeRequest, { method: 'GET' });
console.log(cache.match('test') instanceof Promise); // true
</script>unpkg
<script src="https://unpkg.com/@nextgis/cache"></script>jsdelivr
<script src="https://cdn.jsdelivr.net/npm/@nextgis/cache"></script>We recommend linking to a specific version number /cache@[version]
npm install @nextgis/cacheimport Cache from '@nextgis/cache';
import { sleep } from '@nextgis/utils';
import CancelablePromise from '@nextgis/cancelable-promise';
// Cache simple value
const cache = new Cache();
cache.add('test', 'value');
console.log(cache.match('test')); // 'value'
// Cache is global
const cache2 = new Cache();
console.log(cache.match('test')); // 'value'
// Use callback functions to add promises to the cache
// on add cache a promise from callback will be returned
const onAdd = cache.add('test1', () => new Promise((res) => res('ok')));
console.log(onAdd instanceof Promise); // true
onAdd.then((data) => console.log(data)); // 'ok'
// callback need to protect promise from re-running if cache already set.
let callCount = 0;
const makePromise = function () {
return new Promise((resolve) => {
resolve(callCount++);
});
};
Promise.all(() => [
cache.add('key', makePromise),
cache.add('key', makePromise, { id: 1 }),
cache.add('key', makePromise, { id: 1 }),
cache.add('key', makePromise, { id: 2 }),
cache.add('key', makePromise, { id: 2 }),
]).then((resp) => {
console.log(resp); // [0, 1, 1, 2, 2]
});
const fromCache = cache.match('key', { id: 1 });
console.log(fromCache instanceof Promise); // true
fromCache.then(function (resp) {
console.log(resp);
});
// Match all promises from cache by key
cache.add('key', makePromise); // added to cache
cache.add('key', makePromise, { id: 1 }); // added to the cache
cache.add('key', makePromise, { id: 1 }); // NOT added to the cache
cache.add('key', makePromise, { id: 2 }); // added to the cache
cache.add('key', makePromise, { id: 2 }); // NOT added to the cache
Promise.all(cache.matchAll('key')).then((resp) => {
return console.log(resp); // [3, 4, 5]
});
// With cancelable promise
const cb = () => {
return new CancelablePromise((resolve) =>
sleep(30).then(() => resolve('test')),
);
};
const onAdd = cache.add('test', cb);
const fromCache = cache.match('test');
console.log(onAdd instanceof CancelablePromise); // true
console.log(fromCache instanceof CancelablePromise); // true
onAdd.catch((er) => {
if (er.name === 'CancelError') {
// if a promise fails, the cache is not filled
const fromCacheOnCancel = cache.match('test');
if (!fromCacheOnCancel) {
console.log('Done'); // Done
}
}
});
onAdd.cancel();Check out the API Documentation
Need to fix a bug or add a feature to @nextgis/cache? We provide custom development and support for this software. Contact us to discuss options!
