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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
"use strict";
/*
* asyncStoreHelper wraps asyncStorage so that it is easy to define project
* specific properties. It is similar to PrefsHelper.
*
* e.g.
* const asyncStore = asyncStoreHelper("r", {a: "_a"})
* asyncStore.a // => asyncStorage.getItem("r._a")
* asyncStore.a = 2 // => asyncStorage.setItem("r._a", 2)
*/
function asyncStoreHelper(root, mappings) {
let store = {};
function getMappingKey(key) {
return Array.isArray(mappings[key]) ? mappings[key][0] : mappings[key];
}
function getMappingDefaultValue(key) {
return Array.isArray(mappings[key]) ? mappings[key][1] : null;
}
Object.keys(mappings).map(key =>
Object.defineProperty(store, key, {
async get() {
const value = await asyncStorage.getItem(
`${root}.${getMappingKey(key)}`
);
return value || getMappingDefaultValue(key);
},
set(value) {
asyncStorage.setItem(`${root}.${getMappingKey(key)}`, value);
},
})
);
store = new Proxy(store, {
set(target, property) {
if (!mappings.hasOwnProperty(property)) {
throw new Error(`AsyncStore: ${property} is not defined in mappings`);
}
Reflect.set(...arguments);
return true;
},
});
return store;
}
module.exports = asyncStoreHelper;