nodejs/doc/api/stdio.markdown

console

Stability: 4 - API Frozen

• {Object}

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() 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() where if the expression evaluates as false throw an AssertionError with message.