persistent-objects

Warning: Mad science.

In the first lecture of my first web development course, we were told that javascript had a short memory, and shouldn't be expected to stick around after page refreshes. I made a note to find a way around that when I'd had enough experience, and now that I have, I built this!

Installation

    <script type="application/javascript" src="/path/to/persistient.js"></script>

Browser Support

Persistient objects rely on Object.observe, which is currently only available in chrome. Polyfills are being looked into.

Usage

Basic Usage

A Persistient Object, or "Pobject" is identical to a plain old javascript object, except the values of it's properties survive page refresh.

> var a = Pobject.findOrCreate("a");
> a.b = 1;

PAGE REFRESH

> var a = Pobject.findOrCreate("a");
> console.log(a.b); //1, tada!

But wait, there's more!

> var a = Pobject.findOrCreate("a");
> var b = Pobject.findOrCreate("b");
> a.b = b;
> b.c = 1;

PAGE REFRESH

> var a = Pobject.findOrCreate("a");
> var b = Pobject.findOrCreate("b");
> a.b === b; //true
> a.b.c === 1; //true

So as you can see, all objects are linked by reference, rather than by value, which allows for a rich relational data model. "Awesome! But what if I want to use my own classes?" I hear you say. Easy mode!

Advanced Usage

###es6 classes

class Wizard{
    constructor(name, petType){
        this.name = name;
        this.petType = petType || "Lost"
        this.friends = {};
        this.spells = []; //works just as well with arrays!
    }

    learn(spell){
        this.spells.push(spell);
    }

    befriend(friend){
        this.friends[friend.name] = friend;
    }
}

registerType(Wizard); //Just register your new type with the system, and you're good to go!

###es5 classes

function Wizard (name){
    this.name = name;
    this.petType = petType || "Lost"
    this.friends = {};
    this.spells = [];

    this.learn = function(spell){
        this.spells.push(spell);
    }

    this.befriend = function(friend){
        this.friends[friend.name] = friend;
    }
}

registerType(Wizard);

Once your classes are registered, they provide full CRUD functionality as follows:

###Create

> Wizard.create(id, arg1, arg2, ...);

The create function creates a new persistient object under the given id, overriding anything perviously using it. All arguments after the id will be used in the constructor.

> var wiz = new Wizard(name, pet);

Just using the constructor normally will create a new object with an auto generated unique id.

Any object created (by any of the above methods) will be added to Wizard.items, or Wizard.wizards (pluralised lowercase classname).

###Retrive

> Wizard.find(id);
//or
> Wizard.find({property:searchValue}); //i.e {name:"Luna Lovegood"}

The find function can take either an id, or a mongo style query. If given a query, it will return all that match it as an array. If given an id, will return a singular item. If either method finds nothing, will return undefined.

> Wizard.findOne(id);
//or
> Wizard.findOne({property:searchValue}); //i.e {name:"Luna Lovegood"}

Identical to .find, but will return the first item to match.

> Wizard.findOrCreate(id)

Does what it says on the box. Will return the object referenced by the id, or will create one under it.

###Update

> ginny.name = "Ginny Potter";

That's the beauty of an application that automatically writes it's data to the database (which is in this case, the local cache), updates are super simple.

###Destroy

> Wizard.remove(fred);
> //or
> Wizard.remove(fred.id);

When a persistient object is removed, it is removed from the list of items, and can no longer be found by .find. All it's properties that are not themselves objects are removed from the cache.

> Wizard.obliterate(fred);
> //or
> Wizard.obliterate(fred.id);

When a persistient object is obliterated, it and all decendant objects are removed. So in the above example, if fred.brother was gorge, gorge.remove() would have been called, as well as any object that was a property of gorges, ect.

###Example

var hermoine = new Wizard("Hermoine Granger", "Cat");
var ron = new Wizard("Ron Weasly");

hermoine.befriend(ron);
ron.befriend(hermoine);

hermoine.learn("Wingardium Leviosa");
ron.learn("Wingardium Leviosaah");

PAGE REFRESH

var hermoine = Wizard.findOne({name:"Hermoine Granger"});
var ron = Wizard.findOne({name:"Ron Weasly"});

hermoine.friends["Ron Weasly"] === ron; //true
ron.friends["Hermoine Granger"] === hermoine; //true

ron.friends["Hermoine Granger"].spells // ["Wingardium Leviosa"]
hermoine.friends["Ron Weasly"].spells // ["Wingardium Leviosaah"]

hermoine.remove();
ron.remove();

var hermoine = Wizard.findOne({name:"Hermoine Granger"}); //undefined
var ron = Wizard.findOne({name:"Ron Weasly"});            //undefined

#Developing <<<<<<< HEAD If you want to muck around with the library,

If you want to muck around with the library, all the raw files are in the development folder.

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