ESP32 Non-Volatile Storage reader

A JavaScript browser library for reading ESP32 Non-Volatile Storage (NVS) entries over USB using WebSerial.

Highlights

• Reads specified NVS partitions or auto-detects them using device's partition table
• Supports all NVS types (integers, strings, blobs)
• Communicates directly with the ESP32 over USB using WebSerial
• Efficiently reads just enough data to find what you are looking for
• Can retrieve specific entry or get all entries
• Provides both function-based and class-based interfaces
• Includes built-in output formats for JSON and HTML
• Easily customizable output via user-friendly iterator pattern

Browser Support

WebSerial is a non-standard feature and is only supported in Chromium-based browsers. See CanIUse for browser support.

Live Demos

• Simple example
• JSON example
• WiFi example
• Table example

Install

The library can either be downloaded using NPM or loaded on request from a CDN. Local install is only required for full TypeScript types support.

CDN

Import the library from CDN into your JavaScript code like this:

import { NVS } from "https://cdn.jsdelivr.net/gh/FanatiQS/esp-nvs-js@master/nvs.js";

NPM

Install the library through NPM and then import it into your JavaScript code like this:

npm install fanatiqs/esp-nvs-js

import { NVS } from "esp-nvs-js";

Usage

Other than the limited browser support mentioned above, WebSerial also only works on HTTPS/localhost and can only be triggered by a UserGesture, not on load. This means that all examples need to be called from some kind of user input, like a button press or other form of user initiated trigger.

Example 1

Get the value for a specific entry. Look at examples/simple.html (demo) for a complete example.

const nvs = new NVS(await navigator.serial.requestPort());
const chan = await nvs.get("nvs.net80211", "sta.chan");
console.log(chan);

Example 2

Get all values as JSON. Look at examples/json.html (demo) for a complete example.

const nvs = new NVS(await navigator.serial.requestPort());
await nvs.all();
console.log(nvs.toJSON());

Example 3

Render all values in HTML table. Look at examples/table.html (demo) for a complete example.

const nvs = new NVS(await navigator.serial.requestPort());
await nvs.all();
document.body.appendChild(nvs.toHTML());

Example 4

Get all values through iterator.

const nvs = new NVS(await navigator.serial.requestPort());
await nvs.all();
for (const [ namespace, key, value ] of nvs) {
	console.log(namespace, key, value);
}

Limitations

• No support for encrypted NVS partitions
• No delete or write support

Todo

• Add tests
• Add delete support
• Add write support
• Add support for encrypted partitions