react-async-cache

react-async-cache is a library to cache asynchrone function call between different component.
It was initially build to improve cache of api call with react. This library can be especially useful to cache some fetch query, for example using axios. The concept was inspired from Apollo cache, even if it is far from being comparable.

The library take care to save the response of the async function and share it between components using context api. It will also avoid unnecessary call made simultaneously to the same async function. It will identify the cache id base on the name of the function and the parameters passed. So if you call multiple times the same function with different parameters, it will not use the same cache. Example:

api is an async function
``js
export api = async (param1, param2) => ...
`

`js
call(api, '/counter');
call(api, '/timer');
`
This 2 call to api function will have different cache because they don't share the same parameters.

`js
call(api, '/counter');
call(api, '/counter');
`
This 2 call to api function will have the same cache and api will be called only once.

Example

See full example at here.

!counter-example

counter.js
`jsx
import React from 'react';
import { useAsyncCacheWatch } from 'react-async-cache';
import { api } from './mockapi';

export const Counter = () => {
const { call, response } = useAsyncCacheWatch(api, '/counter');
React.useEffect(() => {
// call api to get current counter value and cache it
// it will avoid unnecessary simultanous call
call();
});
return (



);
}
`

app.js
`jsx
import React from 'react';
import { AsyncCacheProvider } from 'react-async-cache';
import { Counter } from './Counter';

const App = () => {
return (




);
}
`
In this example, without cache there would have been 2 calls to the api, but using react-async-cache there is only 1 call. The library will take care to populate the response to all the components.

update cache

react-async-cache provide as well different way to interact with the cache:

`jsx
import React from 'react';
import { useAsyncCache } from 'react-async-cache';
import { api } from './mockapi';

export const SetCounter = () => {
const { update, cache } = useAsyncCache(api, '/counter');
const onReset = async () => {
// Call api to update the counter
const response = await api('/counter', 'POST', { value: 1 });
// Update the cache to populate the response to the other component
await update(response);
}
const onIncrement = async () => {
// Load count value from cache
const count = cache();
// Call api
const response = await api('/counter', 'POST', { value: count + 1 });
// Update cache
await update(response);
}
return (



);
}
`

How to use it

react-async-cache is using the context api to share the state between component. So the first thing to do is to call the context provider in the root of the app:

`tsx
import { AsyncCacheProvider } from 'react-async-cache';

ReactDOM.render((



), document.getElementById('root'));

`

$3

useAsyncCache hook is mainly to interact with the cache. The hook get some parameters, the first given parameter is the function you want to cache. The next parameters are the parameters you would have providen to the function to cache. This hook return an object of 4 properties: call, update, cache and responses.

`tsx
import { useAsyncCache } from 'react-async-cache';

export const MyComponent = () => {
const { call, update, cache } = useAsyncCache(getItem, 'id-20', { withComment: true });
...
}
`

call is a function that allow to cache the async function. call will return the id of the corresponding response in the cache.

`tsx
async call() => Promise
`

eg.:
`tsx
const id = await call();
`

cache is a function to access the cache. It work the same way as the call function, but it will retrieve the response from the cache, instead to call the async function.

update is a function that allow to update the cache without to make a call to the server. The first parameter is the new response you want to set.

eg.:

`tsx
await update([
{id:'id-1', title: 'hello'},
{id:'id-2', title: 'hello2'},
]);
`

responses is the actual cache representing all the asynchrone call, error and response. To access the cache prefer using the cache function instead.

$3

useAsyncCacheWatch hook is used for watching a specific response, allowing to automatically update the state of a component. This hook return the same attributes as useAsyncCache plus 2 extra attributes response and error.

To use useAsyncCacheWatch, you need to provide the same parameters as for useAsyncCache.

`tsx
import { useAsyncCacheWatch } from 'react-async-cache';

export const MyComponent = () => {
const { call, response, error } = useAsyncCacheWatch(getItem, 'id-20', { withComment: true });
...
}
`

response is the response received after the function has been called.

error is the error received if the function called failed.

$3

useAsyncCacheEffect combine useAsyncCacheWatch with React.useEffect. The following code is very recurrent:

`js
const { call, response } = useAsyncCacheWatch(someAsyncFunc, someParams);
React.useEffect(() => {
call();
});
`

Therefor react-async-cache provide useAsyncCacheEffect to simplify it to:

`js
const { response, call } = useAsyncCacheEffect(someAsyncFunc, someParams);
// or
const { response, call } = useAsyncCacheEffect([], someAsyncFunc, someParams); // where [] is the deps from React.useEffect
`
useAsyncCacheEffect get the same parameters as call function from useAsyncCache.

The first given parameter is the function you want to cache. The next parameters are the parameters you would have providen to the function you want to cache.

You can also provide the deps from React.useEffect` as first parameters, then come the others params.