Increase eventEmitter.maxListeners in inpage script

[danfinlay]

Seems that our new .subscribe() support has introduced an event listener warning to our inpage script:

MaxListenersExceededWarning: "Possible EventEmitter memory leak detected. 11 data listeners added. Use emitter.setMaxListeners() to increase limit"

Reported here.

[bdresser]

fwiw i've seen this error intermittently for the past several months

[hodlbank]

Can confirm.
Our DApp having page with list of "receipts", each receipt watches a contract event.
When there are more than 10 receipts this error happens.

Stack trace (roughly):

EventEmitter?.addListener()
RequestManager.setProvider()
???.packageInit()
new a.web3.eth.Contract()

[hodlbank]

Solution for our DApp is to increase maxListeners of currentProvider upon provider initialization:

// typescript
private tuneUpProvider(provider: Provider): void {
    let providerEE = provider as any;
    if (typeof providerEE.setMaxListeners == 'function') {
      providerEE.setMaxListeners(999);
    }
  }