@green-code/memoize-async

Memoize Async

Memoize the value of any promise or synchronous function.

Generator functions are not supported.

Memoizing the same function with the same arguments while the async operation is still running will result in an undefined result, but you may listen for the result of the event memoizeAsync.operation.complete from wherever it's called.

Installation

npm install

If you intend to use this in an non-Node based environment, for example a browser, you must also run npm add events.

Usage

Initialise With Pre-loaded Data

const memoizeAsync = require("@green-code/memoize-async")({foo: "bar", biz: "baz"});

Get and Set

const hello = async (string) => new Promise(resolve => resolve(`Hello ${string}!`));

// Arguments must be wrapped in an array because they will be passed to your function using the spread operator
memoizeAsync.getAndSet(hello, ["world"]).then(console.log); // Hello world!;
memoizeAsync.getAndSet(hello, ["Joe"]).then(console.log); // Hello Joe!;

Get All

console.log(memoizeAysnc.getAll()); // {'["hello","AsyncFunction","world"]': 'Hello world!','["hello","AsyncFunction","Joe"]': 'Hello Joe!'}

Delete By Key

memoizeAysnc.deleteByKey('["hello","AsyncFunction","Joe"]');
console.log(memoizeAysnc.getAll()); // {'["hello","AsyncFunction","world"]': 'Hello world!'}

Clear All

memoizeAysnc.clear();
console.log(memoizeAysnc.getAll()); // {}

Listening For Events

const EventEmitter = require("events");
const eventEmitter = new EventEmitter();

eventEmitter.on("memoizeAsync.operation.complete", ({key, value}) => {
    // do something
});

Event Names

memoizeAsync.operation.start

When the function is invoked but not yet completed.

memoizeAsync.operation.success.unsaved

The function was called successfully and the value was not saved to memory because it is either undefined, null or an empty string. You might want to check the arguments you pass to the function or check the function itself.

memoizeAsync.operation.success.saved

The function was called successfully and the value was saved to memory.

memoizeAsync.operation.fail

The function returned an error.

memoizeAsync.operation.complete

Always fires whether the value was saved or not.

memoizeAsync.get

Fires when getting an item previously memoized in memory.

memoizeAsync.getall

Fires when getting all items memoized in memory.

memoizeAsync.delete

Fires when deleting a memoized item from memory.

memoizeAsync.queue.add

When a function call is added to the queue. This is ensures the same function with the same arguments isn't called twice.

memoizeAsync.queue.remove

When a function is removed fromm the queue.

memoizeAsync.queue.clear

When the queue is cleared.