@mapado/swr-promise

swr-promise

Install

$ npm install swr-promise

Usage

import swrPromise from "swr-promise";

const fetchData = (url: string) => fetch(url);

const fiveMinute  = 5 * 60 * 1000

const fetchDataSWR = swrPromise(fetchData,{ maxAge: fiveMinute });

fetchDataSWR("https://api.example.com/data")
  .then(console.log)
  .catch(console.error);

API

swrPromise(promiseFn, [options])

Parameters

• promiseFn: The Promise function to be wrapped.
• options(optional): An options object with the following properties:
  • maxAge: Cache validity period (ms), default is 0, when it is Infinity, it is cached permanently
  • swr: Cache expiration tolerance time (ms), default Infinity (stale-while-revalidate)
  • sie: Update error tolerance time (ms), default is Infinity (stale-if-error)
  • gcThrottle: Garbage collection throttling time (ms), the default is 0, when it is 0, no garbage collection is performed
  • cacheFulfilled: Whether to cache the current normal result, the default is true (arguments, value) => boolean
  • cacheRejected: Whether to cache the current exception result, the default is false (arguments, error) => boolean
  • argsEqual(optional): Compares the two argument arrays for equality to ensure correct matching and lookup of cache entries in the cache
  • storeCreator(optional): creates a Map to store cached data, but you can use other media such as SQlite by passing a custom storeCreator function

Returns

• A new function that accepts the same arguments as promiseFn and returns a Promise.

Example

import swrPromise from "swr-promise";

const mock = () =>
  new Promise((resolve) => setTimeout(() => resolve(Math.random()), 1000));

const swrMock = swrPromise(mock, { maxAge: 1000, swr: 1000 });

await swrMock().then(console.log); // 0.9504613827463109
await swrMock().then(console.log); // 0.9504613827463109 same response

// simulate waiting for 1 second
await sleep(1000);

await swrMock().then(console.log); // 0.9504613827463109 same response, but mock function re-executes

LICENSE

This project is licensed under the MIT License.

Contributing

Contributions are welcome! Please open an issue or submit a pull request.

Acknowledgements

This utility function uses:

• concur-promise to prevents duplicate execution of identical Promise calls
• lodash.isequal to compare the arguments
• lodash.throttle to limit the frequency of garbage collection operations.