console

This module provides well known logging facilities for JavaScript programs. This module (partially) implements the CommonJS Console specification.

Console object

The Console object encapsulates all functionality in the console module in the form of a class. The module exports a default instance of this class though more can be created (which is rarely needed).

class console.Console(stdout[, stderr])

Create an instance of a console object.

Arguments:

• stdout – Object representing standard out. It must implement the same API as io.File().
• stderr – Analogous to stdout, but representing the standard error. If omitted stdout is used.

console.Console.console.Console.prototype.assert(expression[, message][, ...])

Simple assertion test using the assert module. The given expression is evaluated and if it’s falsey the given message is given with an AssertionError.

console.assert(false, 'Whoops %s', 'Houston, we\'ve got a problem!');
// AssertionError: Whoops Houston, we've got a problem!

console.Console.console.Console.prototype.log()

Outpits the given data to stdout with a newline. Data is formatted using utils.object.format().

console.log('Hello %s! Here is a number: %d and an object: %j', 'sjs', 42, {foo: 'foo', bar: 'bar'})
// Hello sjs! Here is a number: 42 and an object: {"foo":"foo","bar":"bar"}

console.Console.console.Console.prototype.info()

Alias for console.Console.prototype.log().

console.Console.console.Console.prototype.error()

Similar to console.Console.prototype.log() but it outputs to stderr.

console.Console.console.Console.prototype.warn()

Alias for console.Console.prototype.error().

console.Console.console.Console.prototype.dir(obj[, options])

Inspect the given object using :js:func:`` and print output to stdout.

console.dir(console);
// { log: [Function],
//   info: [Function],
//   warn: [Function],
//   error: [Function],
//   dir: [Function],
//   time: [Function],
//   timeEnd: [Function],
//   trace: [Function],
//   assert: [Function],
//   Console: [Function: Console] }

Note

The customInspect option is ignored if given.

console.Console.console.Console.prototype.time(label)

console.Console.console.Console.prototype.timeEnd(label)

Create a labeled timestamp. When timeEnd is called the time difference is computed and printed to staout.

console.time('foo');
// (wait some time...)
console.timeEnd('foo');
// foo: 6535.996ms

console.Console.console.Console.prototype.trace([message][, ...])

Prints a stack trace at the current position to stderr. If an optional message and formatting options are given the message is formatted using utils.object.format().

console.trace();
// Trace
//     at global (<repl>:1) preventsyield

Functions

console.assert()

console.log()

console.info()

console.warn()

console.error()

console.dir()

console.time()

console.timeEnd()

console.trace()

Functions bound to the default console.Console() instance.