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new CachedMap(name, options)

This class lets you manage a namespaced collection of key-value pairs in the cache, preserving their type if you're using TypeScript:

import {CachedMap} from 'webext-storage-cache';

const users = new CachedMap('users');

// Or in TypeScript
const users = new CachedMap<User>('users');

Note: The name is unique but webext-storage-cache doesn't save you from bad usage. Avoid reusing the same name across the extension with different value types, because it will cause conflicts:

const starredRepos = new CachedMap<Repo[]>('stars', {days: 1});
const starCounts = new CachedMap<number>('stars'); // Bad: they will override each other

name

Type: string

The unique name that will be used in chrome.storage.local as cache:${name}:${key}

options

maxAge

Type: TimeDescriptor
Default: {days: 30}

The amount of time after which the cache item will expire after each .set() call.

CachedMap#get(key)

Returns the cached value of key if it exists and hasn't expired, returns undefined otherwise.

const cache = new CachedMap('users');
const user = await cache.get('sindresorhus');
// It will be `undefined` if it's not found.

CachedMap#set(key, value)

Caches the value for the amount of time specified in the CachedMap constructor. It returns the value itself.

const cache = new CachedMap('users');
const user = await getUser('sindresorhus');
await cache.set('sindresorhus', user); // Cached for 30 days by default

value

Type: JsonValue | undefined (any value that can be serialized as JSON, or undefined)

CachedMap#has(key)

Checks whether the item is in the cache, returns a boolean.

const cache = new CachedMap('users');
const isCached = await cache.has('sindresorhus');
// true or false

CachedMap#delete(key)

Deletes the requested item from the cache.

const cache = new CachedMap('users');

await cache.set('sindresorhus', user);
console.log(await cache.has('sindresorhus')); // true

await cache.delete('sindresorhus');
console.log(await cache.has('sindresorhus')); // false

License

MIT © Federico Brigante