Boilerplate

IndexDB.js

// Load IndexedDB
window.indexedDB = window.indexedDB || window.mozIndexedDB || window.webkitIndexedDB || window.msIndexedDB;
window.tx = window.IDBTransaction || window.webkitIDBTransaction || window.msIDBTransaction;
window.IDBKeyRange = window.IDBKeyRange || window.webkitIDBKeyRange || window.msIDBKeyRange
 
if (!window.indexedDB) {
   window.alert("Your browser doesn't support a stable version of IndexedDB.")
}

// Operations

function operation(type){
    const dbName    = "myDB";
    var request     = indexedDB.open(dbName, 3), db, tx, store, index; // globals
    
    // doesn't execute while retreiving data
    request.onupgradeneeded = function(e) {
        let db = request.result,
        store = db.createObjectStore('logStore', {keyPath: 'id'}),
        index = store.createIndex('date', 'date', {unique: true}); /* ('logStore', {autoIncrement: true}) */
    };
    
    request.onerror = function(e) {
        console.log("ERROR: ", e.target.errorCode)
    };
    
    request.onsuccess = function(e) {
        db          = request.result;
        tx          = db.transaction('logStore', 'readwrite');
        store       = tx.objectStore('logStore');
        dateIndex   = store.index('date')
    
        db.onerror = function(e){
            console.log("DB ERROR: ", e.target.errorCode)
        }
    
        if (type=='putData'){
            _putData();
        } else if (type == 'getData'){
            _getData();
        }
    
        tx.oncomplete = function(){
            db.close()
        }
    }
    
    function _putData(){
        // put in info
        store.put({
            id          : 1,
            date        : '21 Mar 2020 - 6pm',
            head        : 'head1',
            log         : 'log1'
        });
        store.put({
            id          : 2,
            date        : '22 Mar 2020 - 7pm',
            head        : 'head2xx',
            log         : 'log2'
        });
    }
    
    function _getData(){

        // get data
        let atId1   = store.get(1); // key i.e id = 1
        let atDateIdx   = dateIndex.get('22 Mar 2020 - 7pm');
    
        // as asynchronous, use
        atId1.onsuccess = function(){
            console.log(atId1.result);
            console.log(atId1.result.head, atId1.result.log);
        };
        atDateIdx.onsuccess = function(){
            console.log(atDateIdx.result);
            console.log(atDateIdx.result.head, atId1.result.log);
        };
    }
}


// MAIN
// ----
// comment one of two

// 1.
//operation(type="putData")

// 2. After put data / if existing db
operation(type="getData")

list all databases

indexedDB.databases().then(r => console.log(r))

deleteDatabase

indexedDB.deleteDatabase('exactDatabaseName') // get name from indexedDB.databases().then(r => console.log(r))

list all object stores

request.onsuccess = function(e) {
        db          = request.result;
        console.log(db.objectStoreNames)
}

delete object store

request.onsuccess = function(e) {
        db          = request.result;
        console.log(db.deleteObjectStore( xxx ))
}

Note: These are just APIs. Got these info by checking data-members and methods in console for corresponding object. (__proto__)