DynaCache v3
Caches something and provides it immediately.
Preload, refresh features out of the box.
createDynaCache
This factory function creates another function that uses the cache behind this.
Example
Suppose we have this interface of articles
interface ITestArticle {
title: string;
body: string;
}
And this api method that loads the articles from the backend
const apiLoadArticles = async (args: {lang: string, group: string}): Promise<ITestArticle[]> => [];
Let's make api method cacheable version of it
const apiLoadArticlesCacheEngine = createDynaCache({
load: apiLoadArticles,
expireAfterMinutes: 10,
});
The apiLoadArticlesCacheEngine
is na object, with the load(args: TArgs)
method that returns data.
Thanks to typescript, the function has all types obtained from the load
method, for the args and for the output.
So we don't have to define anything to the generics of the createDynaCache
.
Let's use it
apiLoadArticlesCacheEngine.load({lang: 'en', group: 'fashion'}) // We pass the object as we do with the apiLoadArticles
.then(articles => {
// We have types articles here
articles.forEach(article => {
console.log('Title', article.title);
});
});
createDynaCache
Configuration object of the interface ICreateDynaCacheConfig<TArgs, TData, > {
load: (args: TArgs) => Promise<TData>; // The load operation
expireAfterMinutes?: number; // When the cache expires, undefined for none
preload?: boolean; // Preload the data on start
refreshEveryMinutes?: number; // Refresh the data silently on background
}
Invalidate the cache
To invalidate the cache (to clear the content of the cache) call the invalidate()
apiLoadArticlesCacheEngine.invalidate();
Don't forget to free() it!
Cache keeps resources for refreshing, etc.
If you are going to free the owner of it, your have to call the .free()
also!
Just apiLoadArticlesCacheEngine.free()
.
How does it works internally?
The apiLoadArticlesCacheEngine
creates internally small caches for each different args
.
If you ask the same args, then the cached version will be served.
DynaCache
This is how to create a DynaCache class.
Config
interface IDynaCacheConfig<TData> {
load: () => Promise<TData>; // The load operation
expireAfterMinutes?: number; // When the cache expires, undefined for none
preload?: boolean; // Preload the data on start
refreshEveryMinutes?: number; // Refresh the data silently on background
onLoad?: (data: TData) => void; // Called when the data are loaded for any reason
}
Methods
-
load(): Promise<TData>
load from cache or from source if it is not yet cached -
loadFresh(): Promise<TData>
load fresh data (not from cache) -
invalidate(): void
clear the cache, all further loads will be new -
free(): void
destroy the cache (cleans up auto refresh cache)
Properties
-
get size(): number
returns the size of the cache in bytes -
get loadedAt(): number
timestamp when the last load took place -
get lastUsedAt(): number
timestamp when the cache read last time -
get loadCount(): number
how many the cache was updated -
get lastError(): any
last load error
Example
// Factory function that create a DynaCache with specific args and api method
// This function just connects that arguments with the api method
const createLoadArticlesCache = (lang: string, group: string) =>
new DynaCache({
expireAfterMinutes: 10,
load: () => apiLoadArticles(lang, group),
});
// Lets create a cache for the epi
const loadArticlesCache = createLoadArticlesCache('en', 'fashion');
// Lets use it
loadArticlesCache.load(); // The return is always up to date and fast
// Don't forget to free() it to avoid memory leaks!
// This is needed when `expireAfterMinutes` or `refreshEveryMinutes`
loadArticlesCache.free();
// Note, now you cannot use it anymore
Change log
v3
V3 is totally different approach than V2.
V3 offers plus
- preload
- refresh
- cache factory (cache key by args object)
- simpler code (1/4 of the previous one)
v2
For v2 open this page.