Can't subscribe to events via ethers.js and contract.on(event, handler)

[jsdw]

The relevant code:

import * as ethers from 'ethers';

const CONTRACT_ADDRESS = "0x0d73950cfe29ed1e4e21923307d12a06ee20d3c8"
const CONTRACT_ABI = [
  "event MessageChanged(string message)",
  "function message() view returns (string)",
  "function setMessage(string calldata m) external payable",
]

const provider = new ethers.BrowserProvider((window as any).ethereum)

provider.getSigner().then(signer => {
    const contract = new ethers.Contract(CONTRACT_ADDRESS, CONTRACT_ABI, signer)
    contract.on("MessageChanged",() => { /* handle event */ })
})

The main bit of interest here is the contract.on to subscribe to events from my simple smart contract.

Running this in the browser leads to the error:

Error: could not coalesce error (error={ "code": -32603, "data": { "cause": null, "code": -32601, "message": "Method not found" }, "message": "Internal JSON-RPC error." }, payload={ "id": 4, "jsonrpc": "2.0", "method": "eth_newFilter", "params": [ { "address": [ "0x0d73950cfe29ed1e4e21923307d12a06ee20d3c8" ], "topics": [ "0xbb4847942d98bb5bb249692c72ce235605e41502e705831e609875320ef2cac7" ] } ] }, code=UNKNOWN_ERROR, version=6.13.4)

Looks like we don't have an eth_newFilter RPC yet.

A workaround suggested elsewhere was to set polling to true in the provider, ie const provider = new ethers.BrowserProvider((window as any).ethereum, undefined, { polling: true }). However, this exposes a different missing RPC: eth_getLogs.

Thus, I don't seem able to subscribe to events at the mo :)