/*jshint esversion: 6 */
// ==UserScript==
// @name           GM storage wrapper
// @version        1.0
// @description    simple wrapper for GM_storage with added functions
// ==/UserScript==
var gmStorageWrapper = {
options : {
prefix : ''
},
// “Set” means “add if absent, replace if present.”
set : function(key, value) {
let storageVals = this.read(key);
if (typeof storageVals === 'undefined' || !storageVals) {
// add if absent
return this.add(key, value);
} else {
// replace if present
this.write(key, value);
return true;
}
},
// “Add” means “add if absent, do nothing if present” (if a uniquing collection).
add : function(key, value) {
let storageVals = this.read(key, false);
if (typeof storageVals === 'undefined' || !storageVals) {
this.write(key, value);
return true;
} else {
if (this._isArray(storageVals)) { // is array
let index = storageVals.indexOf(value);
if (index !== -1) {
// do nothing if present
return false;
} else {
// add if absent
storageVals.push(value);
this.write(key, storageVals);
return true;
}
} else if (this._isObject(storageVals)) { // is object
// merge obj value on obj
let r###lt,
objToMerge = value;
r###lt = Object.assign(storageVals, objToMerge);
this.write(key, r###lt);
return false;
}
return false;
}
},
// “Replace” means “replace if present, do nothing if absent.”
replace : function(key, itemFind, itemReplacement) {
let storageVals = this.read(key, false);
if (typeof storageVals === 'undefined' || !storageVals) {
// do nothing if absent
return false;
} else {
if (this._isArray(storageVals)) { // is Array
let index = storageVals.indexOf(itemFind);
if (index !== -1) {
// replace if present
storageVals[index] = itemReplacement;
this.write(key, storageVals);
return true;
} else {
// do nothing if absent
return false;
}
} else if (this._isObject(storageVals)) {
// is Object
// replace property's value
storageVals[itemFind] = itemReplacement;
this.write(key, storageVals);
return true;
}
return false;
}
},
// “Remove” means “remove if present, do nothing if absent.”
remove : function(key, value) {
if (typeof value === 'undefined') { // remove key
this.delete(key);
return true;
} else { // value present
let storageVals = this.read(key);
if (typeof storageVals === 'undefined' || !storageVals) {
return true;
} else {
if (this._isArray(storageVals)) { // is Array
let index = storageVals.indexOf(value);
if (index !== -1) {
// remove if present
storageVals.splice(index, 1);
this.write(key, storageVals);
return true;
} else {
// do nothing if absent
return false;
}
} else if (this._isObject(storageVals)) { // is Object
let property = value;
delete storageVals[property];
this.write(key, storageVals);
return true;
}
return false;
}
}
},
get : function(key, defaultValue) {
return this.read(key, defaultValue);
},
// GM storage API
read : function(key, defaultValue) {
return this.unserialize(GM_getValue(this._prefix(key), defaultValue));
},
write : function(key, value) {
return GM_setValue(this._prefix(key), this.serialize(value));
},
delete : function(key) {
return GM_deleteValue(this._prefix(key));
},
readKeys : function() {
return GM_listValues();
},
// /GM Storage API
getAll : function() {
const keys = this._listKeys();
let obj    = {};
for (let i = 0, len = keys.length; i < len; i++) {
obj[keys[i]] = this.read(keys[i]);
}
return obj;
},
getKeys : function() {
return this._listKeys();
},
getPrefix : function() {
return this.options.prefix;
},
empty : function() {
const keys = this._listKeys();
for (let i = 0, len = keys.lenght; i < len; i++) {
this.delete(keys[i]);
}
},
has : function(key) {
return this.get(key) !== null;
},
forEach : function(callbackFunc) {
const allContent = this.getAll();
for (let prop in allContent) {
callbackFunc(prop, allContent[prop]);
}
},
unserialize : function(value) {
if (this._isJson(value)) {
return JSON.parse(value);
}
return value;
},
serialize : function(value) {
if (this._isJson(value)) {
return JSON.stringify(value);
}
return value;
},
_listKeys : function(usePrefix = false) {
const prefixed = this.readKeys();
let unprefixed = [];
if (usePrefix) {
return prefixed;
} else {
for (let i = 0, len = prefixed.length; i < len; i++) {
unprefixed[i] = this._unprefix(prefixed[i]);
}
return unprefixed;
}
},
_prefix : function(key) {
return this.options.prefix + key;
},
_unprefix : function(key) {
return key.substring(this.options.prefix.length);
},
_isJson : function(item) {
try {
JSON.parse(item);
} catch (e) {
return false;
}
return true;
},
_isObject : function(a) {
return (!!a) && (a.constructor === Object);
},
_isArray : function(a) {
return (!!a) && (a.constructor === Array);
}
};