console: console exposing non-implemented methods

[jasnell]

In master, console is now exposing non-implemented methods found generally on the browser side but not currently implemented in Node.js:

james@ubuntu:~/node/node$ node -v
v7.9.0
james@ubuntu:~/node/node$ node
> console.
console.__defineGetter__      console.__defineSetter__      console.__lookupGetter__      console.__lookupSetter__      console.__proto__             console.constructor           console.hasOwnProperty
console.isPrototypeOf         console.propertyIsEnumerable  console.toLocaleString        console.toString              console.valueOf

console.assert                console.dir                   console.error                 console.info                  console.log                   console.time                  console.timeEnd
console.trace                 console.warn

console.Console               console._stderr               console._stdout               console._times

> console.
> .exit
james@ubuntu:~/node/node$ ./node -v
v8.0.0-pre
james@ubuntu:~/node/node$ ./node
> console.
console.__defineGetter__      console.__defineSetter__      console.__lookupGetter__      console.__lookupSetter__      console.__proto__             console.constructor           console.hasOwnProperty
console.isPrototypeOf         console.propertyIsEnumerable  console.toLocaleString        console.toString              console.valueOf

console.assert                console.dir                   console.error                 console.info                  console.log                   console.time                  console.timeEnd
console.trace                 console.warn

console.Console               console._ignoreErrors         console._stderr               console._stderrErrorHandler   console._stdout               console._stdoutErrorHandler   console._times
console.clear                 console.count                 console.debug                 console.dirxml                console.group                 console.groupCollapsed        console.groupEnd
console.markTimeline          console.profile               console.profileEnd            console.table                 console.timeStamp             console.timeline              console.timelineEnd

> console.

For instance, typeof console.group returns function, even tho console.group() is not implemented by Node.js at all currently. Calling these appear to be non-op:

> console.group('test')
undefined
> console.groupEnd()
undefined
>

These appear to originate from V8.

[addaleax]

These are inspector things, see installInspectorConsoleIfNeeded() in bootstrap_node.js. I’m not sure, what do you think Node should do about these? I would be okay with trying to provide these extra methods on Node’s own Console class.

/cc @nodejs/v8-inspector

[SimenB]

Related? #1716

[jasnell]

@addaleax ... curious. ok. We either should be providing implementation or should not be showing them when --inspect is not being used. I'll open a PR with some basic implementations.

[hashseed]

FYI V8 does ship with a console object now. It's implemented through the inspector though.

[Trott]

#14910 PR for the most minimal console.group() and console.groupEnd() implementation I could muster.

[bengl]

There are still a bunch of methods that show up despite not being implemented. Would bypassing setupInspectorConsole() when --inspect/--inspect-brk aren't provided be the correct thing to do here?

There's also the case of the debugger being triggered by SIGUSR1, so maybe it makes sense to keep it there at startup in case SIGUSR1 happens. Replacing console when the signal is caught might be alright, but if anything is holding onto and using references to properties of console, then that could potentially break those use cases unless there's already some internal trickery done in Console.prototype methods to check if (1) debugging is active, and (2) this === global.console, and then in that case defer to the inspector console.

[apapirovski]

@jasnell Should this remain open? As far as I can tell we've implemented some of these since and others have been documented as being inspector-only.

[jasnell]

Should be ok to close at this point