new Console(stdout[, stderr][, ignoreErrors])#

new Console(options)#

• options<Object>
  • stdout<stream.Writable>
  • stderr<stream.Writable>
  • ignoreErrors<boolean> Ignore errors when writing to the underlyingstreams.Default:true.
  • colorMode<boolean> |<string> Set color support for thisConsole instance.Setting totrue enables coloring while inspecting values. Setting tofalse disables coloring while inspecting values. Setting to'auto' makes color support depend on the value of theisTTY propertyand the value returned bygetColorDepth() on the respective stream. Thisoption can not be used, ifinspectOptions.colors is set as well.Default:'auto'.
  • inspectOptions<Object> |<Map> Specifies options that are passed along toutil.inspect(). Can be an options object or, if different optionsfor stdout and stderr are desired, aMap from stream objects to options.
  • groupIndentation<number> Set group indentation.Default:2.

Creates a newConsole with one or two writable stream instances.stdout is awritable stream to print log or info output.stderr is used for warning orerror output. Ifstderr is not provided,stdout is used forstderr.

import { createWriteStream }from'node:fs';import {Console }from'node:console';// Alternatively// const { Console } = console;const output =createWriteStream('./stdout.log');const errorOutput =createWriteStream('./stderr.log');// Custom simple loggerconst logger =newConsole({stdout: output,stderr: errorOutput });// use it like consoleconst count =5;logger.log('count: %d', count);// In stdout.log: count 5const fs =require('node:fs');const {Console } =require('node:console');// Alternatively// const { Console } = console;const output = fs.createWriteStream('./stdout.log');const errorOutput = fs.createWriteStream('./stderr.log');// Custom simple loggerconst logger =newConsole({stdout: output,stderr: errorOutput });// use it like consoleconst count =5;logger.log('count: %d', count);// In stdout.log: count 5copy

The globalconsole is a specialConsole whose output is sent toprocess.stdout andprocess.stderr. It is equivalent to calling:

newConsole({stdout: process.stdout,stderr: process.stderr });copy

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

• value<any> The value tested for being truthy.
• ...message<any> All arguments besidesvalue are used as error message.

console.assert() writes a message ifvalue isfalsy or omitted. It onlywrites a message and does not otherwise affect execution. The output alwaysstarts with"Assertion failed". If provided,message is formatted usingutil.format().

Ifvalue istruthy, nothing happens.

console.assert(true,'does nothing');console.assert(false,'Whoops %s work','didn\'t');// Assertion failed: Whoops didn't workconsole.assert();// Assertion failedcopy

console.clear()#

Whenstdout is a TTY, callingconsole.clear() will attempt to clear theTTY. Whenstdout is not a TTY, this method does nothing.

The specific operation ofconsole.clear() can vary across operating systemsand terminal types. For most Linux operating systems,console.clear()operates similarly to theclear shell command. On Windows,console.clear()will clear only the output in the current terminal viewport for the Node.jsbinary.

console.count([label])#

• label<string> The display label for the counter.Default:'default'.

Maintains an internal counter specific tolabel and outputs tostdout thenumber of timesconsole.count() has been called with the givenlabel.

>console.count()default:1undefined>console.count('default')default:2undefined>console.count('abc')abc:1undefined>console.count('xyz')xyz:1undefined>console.count('abc')abc:2undefined>console.count()default:3undefined>copy

console.countReset([label])#

• label<string> The display label for the counter.Default:'default'.

Resets the internal counter specific tolabel.

>console.count('abc');abc:1undefined>console.countReset('abc');undefined>console.count('abc');abc:1undefined>copy

console.debug(data[, ...args])#

• data<any>
• ...args<any>

Theconsole.debug() function is an alias forconsole.log().

console.dir(obj[, options])#

• obj<any>
• options<Object>
  • showHidden<boolean> Iftrue then the object's non-enumerable and symbolproperties will be shown too.Default:false.
  • depth<number> Tellsutil.inspect() how many times to recurse whileformatting the object. This is useful for inspecting large complicatedobjects. To make it recurse indefinitely, passnull.Default:2.
  • colors<boolean> Iftrue, then the output will be styled with ANSI colorcodes. Colors are customizable;seecustomizingutil.inspect() colors.Default:false.

Usesutil.inspect() onobj and prints the resulting string tostdout.This function bypasses any custominspect() function defined onobj.

console.dirxml(...data)#

• ...data<any>

This method callsconsole.log() passing it the arguments received.This method does not produce any XML formatting.

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

• data<any>
• ...args<any>

Prints tostderr with newline. Multiple arguments can be passed, with thefirst used as the primary message and all additional used as substitutionvalues similar toprintf(3) (the arguments are all passed toutil.format()).

const code =5;console.error('error #%d', code);// Prints: error #5, to stderrconsole.error('error', code);// Prints: error 5, to stderrcopy

If formatting elements (e.g.%d) are not found in the first string thenutil.inspect() is called on each argument and the resulting stringvalues are concatenated. Seeutil.format() for more information.

console.group([...label])#

• ...label<any>

Increases indentation of subsequent lines by spaces forgroupIndentationlength.

If one or morelabels are provided, those are printed first without theadditional indentation.

console.groupCollapsed()#

An alias forconsole.group().

console.groupEnd()#

Decreases indentation of subsequent lines by spaces forgroupIndentationlength.

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

• data<any>
• ...args<any>

Theconsole.info() function is an alias forconsole.log().

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

• data<any>
• ...args<any>

Prints tostdout with newline. Multiple arguments can be passed, with thefirst used as the primary message and all additional used as substitutionvalues similar toprintf(3) (the arguments are all passed toutil.format()).

const count =5;console.log('count: %d', count);// Prints: count: 5, to stdoutconsole.log('count:', count);// Prints: count: 5, to stdoutcopy

Seeutil.format() for more information.

console.table(tabularData[, properties])#

• tabularData<any>
• properties<string[]> Alternate properties for constructing the table.

Try to construct a table with the columns of the properties oftabularData(or useproperties) and rows oftabularData and log it. Falls back to justlogging the argument if it can't be parsed as tabular.

// These can't be parsed as tabular dataconsole.table(Symbol());// Symbol()console.table(undefined);// undefinedconsole.table([{a:1,b:'Y' }, {a:'Z',b:2 }]);// ┌─────────┬─────┬─────┐// │ (index) │ a   │ b   │// ├─────────┼─────┼─────┤// │ 0       │ 1   │ 'Y' │// │ 1       │ 'Z' │ 2   │// └─────────┴─────┴─────┘console.table([{a:1,b:'Y' }, {a:'Z',b:2 }], ['a']);// ┌─────────┬─────┐// │ (index) │ a   │// ├─────────┼─────┤// │ 0       │ 1   │// │ 1       │ 'Z' │// └─────────┴─────┘copy

console.time([label])#

• label<string>Default:'default'

Starts a timer that can be used to compute the duration of an operation. Timersare identified by a uniquelabel. Use the samelabel when callingconsole.timeEnd() to stop the timer and output the elapsed time insuitable time units tostdout. For example, if the elapsedtime is 3869ms,console.timeEnd() displays "3.869s".

console.timeEnd([label])#

• label<string>Default:'default'

Stops a timer that was previously started by callingconsole.time() andprints the result tostdout:

console.time('bunch-of-stuff');// Do a bunch of stuff.console.timeEnd('bunch-of-stuff');// Prints: bunch-of-stuff: 225.438mscopy

console.timeLog([label][, ...data])#

• label<string>Default:'default'
• ...data<any>

For a timer that was previously started by callingconsole.time(), printsthe elapsed time and otherdata arguments tostdout:

console.time('process');const value =expensiveProcess1();// Returns 42console.timeLog('process', value);// Prints "process: 365.227ms 42".doExpensiveProcess2(value);console.timeEnd('process');copy

console.trace([message][, ...args])#

• message<any>
• ...args<any>

Prints tostderr the string'Trace: ', followed by theutil.format()formatted message and stack trace to the current position in the code.

console.trace('Show me');// Prints: (stack trace will vary based on where trace is called)//  Trace: Show me//    at repl:2:9//    at REPLServer.defaultEval (repl.js:248:27)//    at bound (domain.js:287:14)//    at REPLServer.runBound [as eval] (domain.js:300:12)//    at REPLServer.<anonymous> (repl.js:412:12)//    at emitOne (events.js:82:20)//    at REPLServer.emit (events.js:169:7)//    at REPLServer.Interface._onLine (readline.js:210:10)//    at REPLServer.Interface._line (readline.js:549:8)//    at REPLServer.Interface._ttyWrite (readline.js:826:14)copy

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

• data<any>
• ...args<any>

Theconsole.warn() function is an alias forconsole.error().

console.profile([label])#

• label<string>

This method does not display anything unless used in the inspector. Theconsole.profile() method starts a JavaScript CPU profile with an optionallabel untilconsole.profileEnd() is called. The profile is then added totheProfile panel of the inspector.

console.profile('MyLabel');// Some codeconsole.profileEnd('MyLabel');// Adds the profile 'MyLabel' to the Profiles panel of the inspector.copy

console.profileEnd([label])#

• label<string>

This method does not display anything unless used in the inspector. Stops thecurrent JavaScript CPU profiling session if one has been started and printsthe report to theProfiles panel of the inspector. Seeconsole.profile() for an example.

If this method is called without a label, the most recently started profile isstopped.

console.timeStamp([label])#

• label<string>

This method does not display anything unless used in the inspector. Theconsole.timeStamp() method adds an event with the label'label' to theTimeline panel of the inspector.