How to catch WebsocketProvider errors ?

[0xARK]

Hello, all. Here is the code I use :

this.provider = new Ethers.providers.WebSocketProvider(rpc);
try {
    this.provider.on('pending', (txHash) => {
        performActions(txHash);
    });
} catch (e) {
    performActionsFallback();
}

But when an error occured when subscribing to pending event, my catch is not triggered and my app crashes as you can see below (I tried on arbitrum as I know that there is no mempool) :

So, someone know how can I handle this error to avoid that my app crashes ?

[0xARK]

⚠️ This seems to not break anything but this change is not recommended, see answer below

In case of someone is having a similar problem, I have been able to handle these errors by changing this line :

ethers.js/packages/providers/lib/websocket-provider.js

Line 140 in bf0b468

request.callback(error, undefined);

To :

//request.callback(error, undefined);
_this._websocket.emit("error", error)

Then, I have been able to catch error with a simple

this.provider._websocket.on("error", e => { console.log(e); });

[0xARK]

@ricmoo Idk if I can move this to issue or not.

After furthermore research, I came to the following conclusions:

• the above change seems to not break anything but is not good as it does not allow to reject correctly.
• the promise allowing to send websocket subscription request is not catched anywhere.

If you want to fix that in your local npm packages, you need to change:

ethers.js/packages/providers/lib.esm/websocket-provider.js

Line 181 in bf0b468

});

To:

    }).catch(e => _this.emit("subscribeError", e));

This allows you to catch error in the following way :

this.provider = new Ethers.providers.WebSocketProvider(rpc);
this.provider
    .on('pending', (txHash) => {
        performActions(txHash);
    })
    .on('subscribeError', e => {
        performFallbackActions();
    });