A wrapper for node-cache which can be used as a decorator (but not only!) to cache the response of a method. It fully works with promises/async functions. If there is a pending Promise, a new one will not be created, thus saving precious resources.
The primary use case for this library was to enable caching of long running and expensive server-side requests without introducing a lot of complexity to the codebase.
To install simply run:
npm install --save decorator-cache
It should be pretty obvious that you use decorator-cache as a decorator ✨.
(To use decorators you will need Babel, but you already have that anyway, don't you?)
import { cached } from 'decorator-cache';
class ExampleClass {
@cached({ cacheTTL: 60 })
expensiveOperation(param1, param2) {
const result = `${param1} + ${param2}`; // whatever you want to cache
return result;
}
@cached({ cacheTTL: 60 })
async expensiveOperation(param1, param2) {
const result = await axios.get('https://...'); // whatever you want to cache
return result;
}
@cached({ cacheTTL: 60, autoUpdate: true })
expensiveOperationThatShouldAlwaysBePresent(param1) {
const result = `This will auto update, so you never have to wait! Isn't that ${param1}`; // whatever you want to cache
return result;
}
}In those cases, when you want to decorate a simple method, that is not within a class, you can use the same method!
import { cached } from 'decorator-cache';
const myMethod = cached({ cacheTTL: 10, name: 'myMethod' })(() => { // Name parameter is required, when using a non-named function
const result = await axios.get('https://...'); // whatever you want to cache
return result;
});
const myNamedMethod = cached({ cacheTTL: 10 })(function namedMethod() { // Name parameter is not required
const result = await axios.get('https://...'); // whatever you want to cache
return result;
})There's not much you need to worry about:
cacheTTL (default: 10) - time in seconds for how long the result will be cached,
autoUpdate (default: false) - should the value be auto updated when the cache expires. Setting this to true will invoke the method every cacheTTL seconds and will update the cache.
name (default: undefined) - required only if using non-decorator approach for a non-named method.
Note: Bear in mind, that autoUpdate will execute for each different parameters combination, that was invoked after starting up the application. If there can be lots of different combinations - I generally do not suggest using this option, as that might lead to self-destruct 😊
decorator-cacheis using object-hash to hash the parameters of the invoked method. So for each different combination of parameters a hash is generated and a cache record is added using this hash as a key.- Cache instance is global for all methods. After a record expires it is deleted from the cache.
- Promises are supported 🙌.
- Martynas - Initial work - LinkedIn
This project is licensed under the MIT License - see the LICENSE file for details