console

• {Object}

The console functions are synchronous when the destination is a terminal or
a file (to avoid lost messages in case of premature exit) and asynchronous
when it’s a pipe (to avoid blocking for long periods of time).

That is, in the following example, stdout is non-blocking while stderr
is blocking:

In daily use, the blocking/non-blocking dichotomy is not something you
should worry about unless you log huge amounts of data.

Prints to stdout with newline. This function can take multiple arguments in a
-like way. Example:

console.info([data][, …])

Same as console.log.

console.error([data][, …])

Same as console.log but prints to stderr.

Same as console.error.

console.dir(obj[, options])

Uses util.inspect on obj and prints resulting string to stdout. This function
bypasses any custom function on obj. An optional options object
may be passed that alters certain aspects of the formatted string:

• colors - if true, then the output will be styled with ANSI color codes.
  Defaults to false. Colors are customizable, see below.

console.time(label)

Mark a time.

Finish timer, record output. Example:

console.trace(message[, …])

console.assert(value[, message][, …])

Similar to assert.ok(), but the error message is formatted as
util.format(message...).