nodejs/doc/api/stdio.markdown

console

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()

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() for more information.

console.info()

Same as console.log.

console.warn()

console.error()

Same as console.log but prints to stderr.

console.dir(obj)

Uses util.inspect on obj and prints resulting string to stderr.

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()

Print a stack trace to stderr of the current position.

console.assert()

Same as assert.ok().