How to create an indexeddb composite key

Question

I spent hours and hours searching for this one, and just by trial and error was I able to finally find the solution. Logging this in Stack Overflow for future searchers.

Q:

How do I create a composite key in indexeddb?

Keys are created in indexeddb on object stores using the following:

var db; var openRequest = indexedDB.open('myDB', 1); openRequest.addEventListener('error', () => {     console.error('Unable to open db'); }); openRequest.addEventListener('upgradeneeded', function(event){     var store = db.createObjectStore('myStore',          {keyPath: /* composite key */ }     ); }); openRequest.addEventListener('success', function(){     db = openRequest.result; }); 

I have tried placing objects, defining multiple times, how does one create a composite key, or is this a limitation of the API?

Note: If you are looking for how to query a composite key using a range, please check out this post

Answer 1

A:

As it turns out, the answer is very simple, but not documented well anywhere I have looked, and not obvious at first glance. Use an array of strings...

var store = db.createObjectStore('myStore',      {keyPath: ['id1', 'id2']} ); 

Composite indexes can also be created in the same fashion.

For work with composite key data, see the answer below by Malvineous