This module lets you take control over the output from console logging methods in Node.js. Such as prefixing the log statement with timestamp information, log levels, add coloured output and much more.
npm install console-stampYou need to provide the console object to console-stamp in order to patch the builtin console.
require( 'console-stamp' )( console );
console.log('Hello, World!');The default behaviour is to add a prefix to each log statement with timestamp information and log level.
[10.02.2019 15:37:43.452] [LOG] Hello, World!
You can change this by provinding an options object as the second parameter.
require('console-stamp')(console, {
format: ':date(yyyy/mm/dd HH:MM:ss.l)'
} );
console.log('Hello, World!');[2020/01/19 13:56:49.383] Hello, World!
Notice how the log level is suddenly missing. You need to add it specifically to the format string.
require('console-stamp')(console, {
format: ':date(yyyy/mm/dd HH:MM:ss.l) :label'
} );
console.log('Hello, World!');[2020/01/19 23:20:30.371] [LOG] Hello, World!
Read more about how to customize the formatting of the log statement below.
You can also provide a custom console with its own stdout and stderr like this:
const fs = require('fs');
const output = fs.createWriteStream('./stdout.log');
const errorOutput = fs.createWriteStream('./stderr.log');
const logger = new console.Console(output, errorOutput);
require('console-stamp')(logger, {
stdout: output,
stderr: errorOutput
});Everything is then written to the files.
NOTE: If stderr isn't passed, warning and error output will be sent to the given stdout.
console-stamp v3 has been rewritten adding tokens as a new and easier way to customize and extend your logging output.
With that in mind, some consessions has been made and you will probably need to update your console-stamp integration.
options.format is now the place where you provide the format of the logging prefix using tokens.
For example, { pattern: 'dd.mm.yyyy HH:MM:ss.l'} is replaced by { format: ':date(dd.mm.yyyy HH:MM:ss.l)' }.
PS: Providing a string with a date format based on dateformat as a second parameter is still supported.
The log level label (INFO, DEBUG etc.) is now only shown if the token :label is part of the format string in options.format. It is part of the default format.
options.labelSuffix and options.labelPrefix are also gone as now you can provide these values directly in the options.format string.
Here are some examples on how to customize your log statements with console-stamp.
Without any other customizations you can provide the timestamp format directly.
require('console-stamp')( console, 'yyyy/mm/dd HH:MM:ss.l' );To set the timestamp format using the options object you can use the date token.
require('console-stamp')(console, {
format: ':date(yyyy/mm/dd HH:MM:ss.l)'
} );
console.log('Hello, World!');[2020/01/19 23:08:39.202] Hello, World!
console-stamp uses the excellent chalk library to provide coloured output and other styling.
require( 'console-stamp' )( console, {
format: ':date().blue.bgWhite.underline :label(7)'
} );You can also simply place some text in parenthesis, and then add your styling to that.
require( 'console-stamp' )( console, {
format: '(->).yellow :date().blue.bgWhite.underline :label(7)'
} );Note that by sending the parameter --no-color when you start your node app, will prevent any colors from console.
$ node my-app.js --no-colorFor more examples on styling, check out the chalk documentation.
There are only three predefined tokens registered by default. These are:
:date([format][,utc])[.color]
:label([padding])[.color]
:msg[.color]
:date([format][,utc])
- format {String}
Containing the date format based on dateformat
Default: 'dd.mm.yyyy HH:MM:ss.l' - utc {Boolean}
Set totruewill return UTC-time
Default: false
:label([padding])
- padding {Number}
The total length of the label, including the brackets and padding
Default: 7
:msg
- If the
:msgtoken is provided informat, the output from the console will be returned in its place, otherwise the console output will be added as the last output, with no formatting.
To define your own token, simply add a callback function with the token name to the tokens option. This callback function is expected to return a string. The value returned is then available as ":foo()" in this case:
require( 'console-stamp' )( console, {
format: ':foo() :label(7)',
tokens:{
foo: () => {
return '[my prefix]';
}
}
} );
console.log("Bar");[my prefix] [LOG] Bar
The token callback function is called with one argument, representing an Object with the following properties:
method{String}
The invoked methodmsg{String}
The console output as a stringparams{Array}
The token parameters (ex: The token call:label(7)will have params[7])tokens{Object}
All the defined tokens, incl. the defaultsdefaultTokens{Object}
Only the default tokens, even if it's been redefined in options
Here we are making a custom date token called mydate using moment.js to format the date
const moment = require('moment');
moment.locale('ja');
require( 'console-stamp' )( console, {
format: ':mydate() :label(7)',
tokens:{
mydate: () => {
return `[${moment().format('LLLL')}]`;
}
}
} );
console.log('This is a console.log message');
console.info('This is a console.info message');
console.debug('This is a console.debug message');
console.warn('This is a console.warn message');
console.error('This is a console.error message');Result:
[2016年5月12日午前11時10分 木曜日] [LOG] This is a console.log message
[2016年5月12日午前11時10分 木曜日] [INFO] This is a console.info message
[2016年5月12日午前11時10分 木曜日] [DEBUG] This is a console.debug message
[2016年5月12日午前11時10分 木曜日] [WARN] This is a console.warn message
[2016年5月12日午前11時10分 木曜日] [ERROR] This is a console.error message
The option.extend option enables the extension or modification of the logging methods and their associated log levels:
The default logging methods and their log levels are as follows:
levels = {
error: 1,
warn: 2,
info: 3,
log: 4,
debug: 4
};The extend option enables the usage of custom console logging methods to be used with this module, for example:
// Extending the console with a custom method
console.fatal = function(msg) {
console.org.error(msg);
process.exit(1);
}
// Initialising the output formatter
require( 'console-stamp' )( console, {
extend: {
fatal: 1
}
} );Note how the console.org.error method used in the custom method. This is to prevent circular calls to console.error
require( 'console-stamp' )( console, [options] );The global console or custom console.
The second parameter is an object with several options. As a feature this parameter can be a string containing the date-format.
-
options.format {String}
A string with date format based on dateformat
Default: ':date(dd.mm.yyyy HH:MM:ss.l) :label' -
options.tokens {Object}
Containing token-functions. See example here. -
options.include {Array}
An array containing the methods to include in the patch
Default: ["debug", "log", "info", "warn", "error"] -
options.level {String}
A string choosing the most verbose logging function to allow.
Default:log -
options.extend {Object}
An object describing methods and their associated log level, to extend the existingmethod <-> log levelpairs.
For an example see Custom methods. -
options.stdout {WritableStream}
A customstdoutto use with custom console.
Default:process.stdout -
options.stderr {WritableStream}
A customstderrto use with custom console.
Default:options.stdoutorprocess.stderr -
options.preventDefaultMessage {Boolean}
If set totrueConsole-stamp will not print out the standard output from the console. This can be used in combination with a custom message token.
Default:false
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