JavaScript
👋 Hackable console logger

Signale

👋 Hackable console logger

Description

Hackable and configurable to the core, signale can be used for logging purposes, status reporting, as well as for handling the output rendering process of other node modules and applications.

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Highlights

• 15 out-of-the-box loggers
• Hackable to the core
• Clean and beautiful output
• Integrated timers
• Custom pluggable loggers
• Filename, date and timestamp support
• Scoped loggers and timers
• Simple and minimal syntax
• Globally configurable through package.json
• Overridable configuration per file and logger

Contents

• Description
• Highlights
• Install
• Usage
• Configuration
• API
• Development
• License

Install

npm install signale

Usage

Default Loggers

Import signale and start using any of the default loggers.

const signale = require('signale');

signale.success('Operation successful');
signale.debug('Hello', 'from', 'L59');
signale.pending('Write release notes for 1.2.0');
signale.fatal(new Error('Unable to acquire lock'));
signale.watch('Recursively watching build directory...');
signale.complete({prefix: '[task]', message: 'Fix issue #59', suffix: '(@klauscfhq)'});

Custom Loggers

To create a custom logger define an options object yielding a types field with the logger data and pass it as argument to a new signale instance.

const {Signale} = require('signale');

const options = {
  scope: 'custom',
  types: {
    remind: {
      badge: '**',
      color: 'yellow',
      label: 'reminder'
    },
    santa: {
      badge: '🎅',
      color: 'red',
      label: 'santa'
    }
  }
};

const custom = new Signale(options);
custom.remind('Improve documentation.');
custom.santa('Hoho! You have an unused variable on L45.');

Additionally, all default loggers can be overridden to your own preference.

Here is an example where we override the default error and success loggers.

const {Signale} = require('signale');

const options = {
  types: {
    error: {
      badge: '!!',
      color: 'red',
      label: 'fatal error'
    },
    success: {
      badge: '++',
      color: 'green',
      label: 'huge success'
    }
  }
};

const signale = new Signale();
signale.error('Default Error Log');
signale.success('Default Success Log');

const custom = new Signale(options);
custom.error('Custom Error Log');
custom.success('Custom Success Log');

The options object can hold the scope and types attributes, where the first corresponds to the name of the scope the logger is reporting from and the second is where the objects named after the custom loggers reside.

scope

• Type: String

Name of the scope.

types

• Type: Object

Holds the configuration of the custom and default loggers.

badge

• Type: String

The icon corresponding to the logger.

label

• Type: String

The label used to identify the type of the logger.

color

• Type: String

The color of the label, can be any of the foreground colors supported by chalk.

Scoped Loggers

To create a scoped logger from scratch, define the scope field inside the options object and pass it as argument to a new signale instance.

const {Signale} = require('signale');

const options = {
  scope: 'global scope'
};

const global = new Signale(options);
global.success('Successful Operation');

To create a scoped logger based on an already existing one, use the scope() function, which will return a new signale instance, inheriting all custom loggers, timers and configuration from the initial one.

const signale = require('signale');

const global = signale.scope('global scope');
global.success('Hello from the global scope');

function foo() {
  const outer = global.scope('outer', 'scope');
  outer.success('Hello from the outer scope');
  
  setTimeout(() => {
    const inner = outer.scope('inner', 'scope'); 
    inner.success('Hello from the inner scope');
  }, 500);
}

foo();

Timers

Timer are managed by the time() and timeEnd() functions. A unique label can be used to identify a timer on initialization, though if none is provided the timer will be assigned one automatically. In addition, calling the timeEnd() function without a specified label will have as effect the termination of the most recently initialized timer, that was created without providing a label.

const signale = require('signale');

signale.time('test');
signale.time();
signale.time();

setTimeout(() => {
  signale.timeEnd();
  signale.timeEnd();
  signale.timeEnd('test');
}, 500);

Configuration

Global

To enable global configuration define the options under the signale namespace in your package.json.

The following illustrates all the available options with their respective default values.

{
  "signale": {
    "displayScope": true,
    "displayBadge": true,
    "displayDate": false,
    "displayFilename": false,
    "displayLabel": true,
    "displayTimestamp": false,
    "underlineLabel": true,
    "underlineMessage": false
  }
}

Local

To enable local configuration call the config() function on your signale instance. Local configurations will always override any pre-existing configuration inherited from package.json.

In the following example, loggers in the foo.js file will run under their own configuration, overriding the package.json one.

// foo.js
const signale = require('signale');

// Overrides any existing `package.json` config
signale.config({
  displayFilename: true,
  displayTimestamp: true,
  displayDate: false
}); 

signale.success('Hello from the Global scope');

Also, scoped loggers can have their own independent configuration, overriding the one inherited by the parent instance or package.json.

// foo.js
const signale = require('signale');

signale.config({
  displayFilename: true,
  displayTimestamp: true,
  displayDate: false
});

signale.success('Hello from the Global scope');

function foo() {
  // `fooLogger` inherits the config of `signale`
  const fooLogger = signale.scope('foo scope');

  // Overrides both `signale` and `package.json` configs
  fooLogger.config({
    displayFilename: true,
    displayTimestamp: false,
    displayDate: true
  });

  fooLogger.success('Hello from the foo scope');
}

foo();

API

signale.<logger>(message[, message]|messageObj|errorObj)

logger

• Type: Function

Can be any default or custom logger.

message

• Type: String

Can be one or more comma delimited strings.

const signale = require('signale');

signale.success('Successful operation');
//=> ✔  success  Successful operation

signale.success('Successful', 'operation');
//=> ✔  success  Successful operation

errorObj

• Type: Error Object

Can be any error object.

const signale = require('signale');

signale.error(new Error('Unsuccessful operation'));
//=> ✖  error  Error: Unsuccessful operation
//        at Module._compile (module.js:660:30)
//        at Object.Module._extensions..js (module.js:671:10)
//        ...

messageObj

• Type: Object

Can be an object holding the prefix, message and suffix attributes, with prefix and suffix always prepended and appended respectively to the logged message.

const signale = require('signale');

signale.complete({prefix: '[task]', message: 'Fix issue #59', suffix: '(@klauscfhq)'});
//=> [task] ☒  complete  Fix issue #59 (@klauscfhq)

signale.scope(name[, name])

Defines the scope name of the logger.

name

• Type: String

Can be one or more comma delimited strings.

const signale = require('signale');

const foo = signale.scope('foo'); 
const fooBar = signale.scope('foo', 'bar');

foo.success('foo');
//=> [foo] › ✔  success  foo

fooBar.success('foo bar');
//=> [foo] [bar] › ✔  success  foo bar

signale.unscope()

Clears the scope name of the logger.

const signale = require('signale');

const foo = signale.scope('foo'); 

foo.success('foo');
//=> [foo] › ✔  success  foo

foo.unscope();

foo.success('foo');
//=> ✔  success  foo

signale.config(settingsObj)

Sets the configuration of an instance overriding any existing global or local configuration.

settingsObj

• Type: Object

Can hold any of the documented options.

// foo.js
const signale = require('signale');

signale.config({
  displayFilename: true,
  displayTimestamp: true,
  displayDate: true
});

signale.success('Successful operations');
//=> [2018-5-15] [11:12:38] [foo.js] › ✔  success  Successful operations

signale.time([, label])

• Return Type: String

Sets a timers and accepts an optional label. If none provided the timer will receive a unique label automatically.

Returns a string corresponding to the timer label.

label

• Type: String

Label corresponding to the timer. Each timer must have its own unique label.

const signale = require('signale');

signale.time();
//=> ▶  timer_0  Initialized timer...

signale.time();
//=> ▶  timer_1  Initialized timer...

signale.time('label');
//=> ▶  label    Initialized timer...

signale.timeEnd([, label])

• Return Type: Object

Deactivates the timer to which the given label corresponds. If no label is provided the most recent timer, that was created without providing a label, will be deactivated.

Returns an object {label, span} holding the timer label and the total running time.

label

• Type: String

Label corresponding to the timer, each timer has its own unique label.

const signale = require('signale');

signale.time();
//=> ▶  timer_0  Initialized timer...

signale.time();
//=> ▶  timer_1  Initialized timer...

signale.time('label');
//=> ▶  label    Initialized timer...

signale.timeEnd();
//=> ◼  timer_1  Timer run for: 2ms

signale.timeEnd();
//=> ◼  timer_0  Timer run for: 2ms

signale.timeEnd('label');
//=> ◼  label    Timer run for: 2ms

Development

For more info on how to contribute to the project, please read the contributing guidelines.

• Fork the repository and clone it to your machine
• Navigate to your local fork: cd signale
• Install the project dependencies: npm install or yarn install
• Lint code for errors: npm test or yarn test

Team

• Klaus Sinani (@klauscfhq)

License

MIT