A Map sub-class backed by a persistant store
This script should not be not be installed directly. It is a library for other scripts to include with the meta directive // @require https://update.greasyfork.org/scripts/31448/206062/data-cachejs.js
// ==UserScript==
// @name data-cache.js
// @version 1.0.0
// @description A Map sub-class backed by a persistant store
// ==/UserScript==
/* jshint asi: true, esnext: true */
DataCache = (() => {
const NORMAL = 'font-weight: normal; text-decoration: none; color: black'
const ERROR = 'font-weight: bold; color: #f4f'
const LINK = 'color: #05f; text-decoration: underline'
const BOLD = 'font-weight: bold'
const BLUE = 'color: #05f'
// --------------------------------------------------------------------
function* entries(v) {
if (typeof v !== 'object') {
throw new TypeError(`Non-object argument passed to entries(v)`, v)
}
if (typeof v.entries === 'function') {
yield* v.entries()
} else {
for (const k of Object.keys(v)) {
const val = [ k, v[k] ]
yield val
}
}
}
// --------------------------------------------------------------------------
class DataCache extends Map {
constructor({ getter, setter = null, key = null, debug = false }) {
super()
setter = setter || getter
if (key) {
this._getter = () => getter(key)
this._setter = value => setter(key, value)
} else {
this._getter = getter
this._setter = setter || getter
}
this._key = key
this._debug = typeof setter === 'boolean' ? setter : debug
this.load()
}
// ------------------------------------------
_set(k, v) {
if (v === super.get(k)) {
return false
}
super.set(k, v)
return true
}
// ------------------------------------------
set(k, v) {
if (this._set(k, v)) {
this.save()
}
}
// ------------------------------------------
delete(k) {
if (super.has(k)) {
super.delete(k)
this.save()
}
}
// ------------------------------------------
clear() {
if (this.size > 0) {
super.clear()
this.save()
}
}
// ------------------------------------------
update(obj) {
let changed = false
for (const [ k, v ] of entries(obj)) {
changed = this._set(k, v) || changed
}
if (changed) {
this.save()
}
return changed
}
// ------------------------------------------
replace(obj) {
let changed = false
if (this.size > 0) {
super.clear()
changed = true
}
for (const [ k, v ] of entries(obj)) {
changed = this._set(k, v) || changed
}
if (changed) {
this.save()
}
return changed
}
// ------------------------------------------
toJSON() {
return [...this.entries()]
.reduce((obj, [ k, v ]) => Object.assign(obj, { [k]: v }), {})
}
// ------------------------------------------
save() {
try {
const json = this.toJSON()
const jstr = JSON.stringify(json, null, this._debug * 2)
// GM_setValue(this._key, jstr)
this._setter(json)
this._log(`save(): ${this.size} items\n\n${jstr}`)
} catch (ex) {
this._log(`save(): error: ${ex}`)
}
}
// ------------------------------------------
load(json) {
super.clear()
try {
// json = json || JSON.parse(GM_getValue(this._key))
json = json || this._getter()
for (const [ k, v ] of entries(json)) {
super.set(k, v)
}
this._log(`load(): ${this.size} items\n\n${JSON.stringify(json, null, 2)}`)
}
catch (ex) {
this._log(`load(): error: ${ex}`)
}
}
// ------------------------------------------
edit(text) {
const res = window.prompt(text, JSON.stringify(this.toJSON(), null, 2))
if (typeof res !== 'string') return
try {
const json = JSON.parse(res)
if (this.replace(json)) {
this._log(`edit(): ${this.size} items\n\n${JSON.stringify(json, null, 2)}`)
}
} catch (ex) {
this._log(`edit(): error: ${ex}`)
}
}
// ------------------------------------------
_log(msg) {
if (this._debug) {
const ks = this._key ? `key: %c'${this._key}'%c` : '%c%c'
console.info(`DataCache(${ks}): ${msg}`, LINK, NORMAL)
}
}
// ------------------------------------------
toString() {
const ks = this._key ? `key: '${this._key}', ` : ''
const kl = [...this.keys()].map(String).join(', ')
return `DataCache(${ks}debug: ${this._debug}): [ ${kl} ]`
}
// ------------------------------------------
dump() {
// this._log(JSON.stringify(this.toJSON(), null, 2))
const el = [...this.entries()]
.map(([ key, value ]) => ({ key, value }))
console.table(el)
}
}
DataCache[Symbol.toStringTag] = 'DataCache'
// --------------------------------------------------------------------------
return DataCache
})()