simple_js_cache_idb

fast and simple persistent (async and sync) dual-layer cache for ES6 browser application data

Features

• can handle integer keys
• lightweight ( no time or object age tracking )
• dual layer ( Map() object and indexedDB )
• generally non-blocking
• quick sync reads are available, if the item has already been read

Caveats

• Assumes localStorage/IndexedDB capability in browser ( and assumes ES6 )
• Should return empty object if doesn't exist in cache (so instead of checking for null, check object length)
• Scope of resolving function may be different (so be wary of using 'this' identifier, or use arrow functions! )
• Async operation: may mutate the item (by set or update) before reading (get) is accomplished
• May not be production ready -> suggest a fix it if you find something

Obscure Caveats

• Does not check for duplicates, there will be unexpected behavior if you try to use objects as keys (since the objects may have different memory instances)

Basic Functions and Possible Usage

• testCacheStorageP

testCacheStorageP().then( ()=>{ console.log('browser uses indexedDb.');}) .catch( (err)=>{ alert('This browser is not supporting indexedDb! Please use an ES6 compliant browser. Close tab.')});

• setCacheStorageP

setCacheStorageP(22, {NAME:'my stuff',myID:22}).then(()=> { });

• getCacheStorageP

getCacheStorageP(22).then( (rslt)=> { console.log('rslt from 22 is '); console.log(rslt); } );

• upsertCacheStorageP

upsertCacheStorageP(22, {NAME:'my stuff 2',ID2:122}).then( ()=> { });

• deleteCacheStorageP

delCacheStorageP(22);

Synchronous Usage - direct read of Level 1 cache map

• getCacheStorageL1

var myData = getCacheStorageL1(22)

Example

• a usage example snippet for a Vue JS project is also included here

•    recommended version is simple_js_cache_idb.js ( uses idb-keyval.JS )
  

On Server

This is a frontend module - I believe it could modified for use in Node.js