webstorage-decorators/README.md

# WebStorage Decorators
A Javascript library that adds property decorators to sync a class property with the local or session storage.

## Quick Setup
 1. Install with: `npm install --save webstorage-decorators`
 2. Add the decorator to your property and use as normal!
 ```typescript
import {LocalStorage, SessionStorage} from 'webstorage-decorators';
 
export class MyCustomClass {
     @LocalStorage({key: 'site_theme', default: 'light_theme'}) theme: string;
     @SessionStorage({encryptWith: config.entryptionKey}) thisUser: User;
     
     constructor() {
        console.log(this.theme, localStorage.getItem('theme')); // Output: 'light_theme', 'light_theme'
        console.log(this.user, localStorage.getItem('user')); // Output: null, undefined
        user = {first: 'John', last: 'Smith', ...}
        console.log(this.user, this.user == localStorage.getItem('user')); // Output: {first: 'John', last: 'Smith', ...}, true
    }
}
 ```

## Caveats
Impure functions don't use the Object's setter preventing the storage from being updated. To prevent this use a pure
function or save it manually by reading the variable. (Reading triggers change detection & save if there are differences)
```typescript
@LocalStorage([1, 2]) example: number[];
example.push(3) // Impure & won't update storage
console.log(localStorage.getItem('example')) // Output: [1, 2];
example; // Trigger save
console.log(localStorage.getItem('example')) // Output: [1, 2, 3];

// OR

example = example.concat([3]); // Pure function requires you to use the setter triggering automatic saving
```