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!

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)

@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