@gleaner/tracker/src/cache.js

A JavaScript tracking library with ecommerce support

import { hasLocalStorage } from './utils'

const HAS_LOCAL_STORAGE = hasLocalStorage()

/*
	A wrapper over localStorage, which prefixes all items with a cache name
*/
class Cache {

	/*
		@param {String}
	*/
	constructor(name) {
		this.name = name;
		this.keys = {};
		this.keyName = this.name + "keys";

		if (HAS_LOCAL_STORAGE) {
			// attempt to continue where left off...
			this._loadKeys();
		}
	}

	/*
		@param {String}
		@param {Object}
	*/
	add(key, value) {
		if (HAS_LOCAL_STORAGE) {
			const keyName = this.name + key;
			this.keys[keyName] = true;
			this._storeKeys();
			localStorage.setItem(keyName, JSON.stringify(value));
		}
	}

	/*
		@param {String}
	*/
	delete(key) {
		if (HAS_LOCAL_STORAGE) {
			const keyName = this.name + key;
			delete this.keys[keyName];
			this._storeKeys();
			// when removed last one, could also remove the keys map...
			localStorage.removeItem(keyName);
		}
	}

	/*
		@returns {Array} 
	*/
	getAll() {
		let events = [];
		if (HAS_LOCAL_STORAGE) {
			events = this._keysAsArray().map((key) => JSON.parse(localStorage.getItem(key)));
		}
		return events;
	}

	deleteAll() {
		for (let key in this.keys)
			localStorage.removeItem(key);
		this.keys = {};
		localStorage.removeItem(this.keyName);
	}

	/*
		@returns {Array}
	*/
	_keysAsArray() {
		let keys = [];
		for (let key in this.keys)
			keys.push(key);
		return keys;
	}

	_storeKeys() {
		localStorage.setItem(this.keyName, JSON.stringify(this.keys));
	}

	_loadKeys() {
		this.keys = JSON.parse(localStorage.getItem(this.keyName)) || {};
	}
}

export default Cache;