Provider instance is created even when MetaMask is not installed

[johnmendonca]

I am using this package to work around a Firefox issue where the eth provider cannot be injected: MetaMask/metamask-extension#3133

On Chromium with no metamask extension installed, this package still creates a full provider object, though some of the properties are undefined.

I am just wondering what is the correct way to check if the provider is good to use. I am planning for now to check the value of chainId, but I don't know if this is actually a bug.

Here is the console.log output for the provider:

Proxy {_events: {…}, _eventsCount: 1, _maxListeners: 100, isMetaMask: true, _state: {…}, …}
[[Handler]]: Object
deleteProperty: () => true
__proto__: Object
[[Target]]: MetamaskInpageProvider
autoRefreshOnNetworkChange: false
chainId: undefined
enable: ƒ ()
isMetaMask: true
networkVersion: undefined
request: ƒ ()
selectedAddress: null
send: ƒ ()
sendAsync: ƒ ()
_events: {connect: ƒ}
_eventsCount: 1
_handleAccountsChanged: ƒ ()
_handleDisconnect: ƒ ()
_maxListeners: 100
_metamask: Proxy {isUnlocked: ƒ, requestBatch: ƒ, isEnabled: ƒ, isApproved: ƒ}
_publicConfigStore: ObservableStore {_events: {…}, _eventsCount: 1, _maxListeners: undefined, _state: {…}}
_rpcEngine: RpcEngine {_events: {…}, _eventsCount: 0, _maxListeners: undefined, _middleware: Array(3)}
_rpcRequest: ƒ ()
_sendSync: ƒ ()
_state: {sentWarnings: {…}, isConnected: true, accounts: undefined, isUnlocked: undefined}
_warnOfDeprecation: ƒ ()
_web3Ref: undefined
__proto__: SafeEventEmitter
[[IsRevoked]]: false

[johnmendonca]

It's possible that I did have metamask installed at one point and have deleted since then. I am looking around chrome://about to see if I can find any local data that might be left behind, but I don't know exactly where it would be.

[rekmarks]

There's an event pair, connect/disconnect, and a related method, isConnected, that are supposed to be used for this purpose, but unfortunately they're not correctly implemented yet. I'll keep this issue open until they are.

Meanwhile, checking if the chainId is undefined is a good solution. The chainId is only populated if the provider successfully connects to MetaMask, so its absence implies the absence of MetaMask.