memory-manager-service

Memory Manager

This service can be used to generate an internal private data that gets automatically disposed when it's not used anymore.

Imagine it as a more advanced WeakMap with an internal Garbage Collector that tries to keep itself clean and tidy.

The Garbage Collector is executed inside ad web worker which avoid that the data processing affects the main UI thread.

How to install

Download the package from npm

npm install memory-manager-service

And then inport it in your code

import Memory from 'memory-manager-service';

How to use

const obj = {};
 
// Initialise the data.
Memory.create(obj);
 
// An id for the data is automatically generated.
const id = Memory.get(obj, "id");
 
// You can store all the data you want passing property name and value.
Memory.set(obj, "test", true);
// Or using the update method
Memory.update(obj, {
    "data": "test"
});
 
// You can get a reference to the original object
console.log(Memory.reference(id) === obj); // true

You can create cross references between data objects by storing the data inside another object.

import Memory from 'memory-manager-service';
 
const obj = {};
const linked = {};
 
// Initialise the data.
Memory.create(obj);
 
// Store the cross reference
Memory.create(linked, {
    "reference": obj
});

This will stop the obj data to be garbage collected until the linked object is not disposed.

Garbage collection can be forced manually, even if the object is cross referenced.

// To force an object to be disposed even if it has been recently updated and/or is cross referenced.
Memory.dispose(obj);
 
console.log(Memory.get(linked, "reference")); // null
 
// Force a garbage collection
Memory.flush();

Array Proxies

In order to keep the garbage collector always up to date, whenever you store an array inside a data object, this will replaced with a Proxy object that will work as a middlewher between you and the actual array. The object itself will work exactly as an array, but it will look weird if you log it on the console.

const arr = ["My Array"];
 
Memory.set(obj, "arr", arr);
 
const proxy = Memory.get(obj, "arr");
 
console.log(proxy); // Proxy {0: "My Array"}
console.log(proxy[0]); // "My Array"
console.log(proxy.length); // 1
console.log(Array.isArray(proxy)); // true
console.log(proxy === arr); // false

Use case

It's not really up to me to tell you how to use the data. In my case, I created this service in order to be able to create composed classes (like mixins), but with a common private area where data can be easily passed across all the composing classes.

Anyway, here is a very simple example on how to use the data:

import Memory from 'memory-manager-service';
 
class Person {
    constructor() {
        Memory.create(this, {
            "name": ""
        });
    }
    
    get id() {
        return Memory.get(this, "id");
    }
    
    get name() {
        return Memory.get(this, "name");
    }
    
    set name(value) {
        Memory.set(this, "name", value);
    }
}

Callbacks

The service will allow you to add callbacks for each object to monitor whenever the object is updated and/or disposed.

const person = new Person();
 
Memory.onUpdate(person, () => console.log(`Hello, ${person.name}!`));
Memory.onDispose(person, () => console.log(`Oh no! They disposed ${person.name}!`));
 
person.name = "Kenny"; // Hello, Kenny!
Memory.dispose(person); // Oh no! They disposed Kenny!