mirror of
https://github.com/nodejs/node.git
synced 2024-11-30 07:27:22 +01:00
5fc8efb87d
The console module has always been called 'stdio' in the
table-of-contents, but nowhere else, since its name is
'console'. This makes it difficult to find.
This is a back-port of commit 226a20d from the master branch.
76 lines
1.9 KiB
Markdown
76 lines
1.9 KiB
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.
|
|
|
|
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:
|
|
|
|
$ node script.js 2> error.log | tee info.log
|
|
|
|
In daily use, the blocking/non-blocking dichotomy is not something you
|
|
should worry about unless you log huge amounts of data.
|
|
|
|
|
|
## 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`.
|
|
|
|
[assert.ok()]: assert.html#assert_assert_value_message_assert_ok_value_message
|
|
[util.format()]: util.html#util_util_format_format
|