nodejs/doc/api/stdio.markdown

# console

    Stability: 4 - API Frozen

* {Object}

<!--type=global-->

For printing to stdout and stderr.  Similar to the console object functions
provided by most web browsers, here the output is sent to stdout or stderr.

## console.log([data], [...])

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

    console.log('count: %d', count);

If formatting elements are not found in the first string then `util.inspect`
is used on each argument.
See [util.format()](util.html#util.format) for more information.

## console.info([data], [...])

Same as `console.log`.

## console.error([data], [...])

Same as `console.log` but prints to stderr.

## console.warn([data], [...])

Same as `console.error`.

## console.dir(obj)

Uses `util.inspect` on `obj` and prints resulting string to stdout.

## console.time(label)

Mark a time.

## console.timeEnd(label)

Finish timer, record output. Example:

    console.time('100-elements');
    for (var i = 0; i < 100; i++) {
      ;
    }
    console.timeEnd('100-elements');

## console.trace(label)

Print a stack trace to stderr of the current position.

## console.assert(expression, [message])

Same as [assert.ok()](assert.html#assert_assert_value_message_assert_ok_value_message)
where if the `expression` evaluates as `false` throw an AssertionError with `message`.