r-console

RConsole is a library that helps display realtime information in the console. It adds a concept of Bar - group of lines sticked to the bottom of the console. Bars make possible to display general information all the time despite other printed messages. Each bar can be updated asynchronous and independently. All these features makes possible to create console-based dashboards easily.

Console layout

All messages will be printed above bottom bars. There are 2 bottom bars. They will always be displayed at the bottom of the console.

$ Some text goes here


====================
Sticky bottom bar 1
====================
Sticky bottom bar 2
====================

Install

$ npm install @wheercool/r-console

Features:

• Colored messages
• Sticky bottom bars

Colored messages

Wrapping message with color tag will change the color of the text inside this tag.

To run it locally:

$ npm run example1

const { RConsole } = require('r-console');

RConsole.print('Simple message');
RConsole.print('<red>Colored message</red>');
RConsole.print('<magenta>Colors <red>can be nested</red>, cool!</magenta>')

Available colors:

• red
• green
• yellow
• blue
• magenta
• cyan
• white
• black

Sticky bottom bars

It is possible to add multiple bottom bars. All printed messages (RConsole.print) will appear above added bars. It is handy to display monitoring information in that way.

Progress bar example

To run it locally:

$ npm run example2

const { RConsole } = require('r-console');

const bottomBar = RConsole.addBar({
 size: 3, // 3 lines height
 template: ({progress}) => [
   `<cyan>=====================</cyan>`,
   `<cyan>Progress: <yellow>${progress.toFixed(2)}%</yellow></cyan>`,
   `<cyan>=====================</cyan>`
 ]
});

let progress = 0;
bottomBar.update({ progress });
RConsole.print('We can print some message');
RConsole.print('But bottomBar will be displayed always at the bottom');

// Emulates progress
let handle = setInterval(() => {
    progress += Math.random() * 20;
    if (progress >= 100) {
      progress = 100;
      clearInterval(handle);
    }
    bottomBar.update({progress}) // update bottomBar value. All previously printed messages will stay on screen.
}, 500);

Multiple independent bars

It is possible to add more than one bar and update them independently.

To run it locally:

$ npm run example3

const { RConsole} = require('r-console');

const memoryUsage = RConsole.addBar({
  size: 2,
  template: (memory) => [
    `<magenta>=====================</magenta>`,
    `<magenta>Memory: <red>${(memory / 1024 / 1024).toFixed(2)} Mb</red></magenta>`
  ]
})

const progressBar = RConsole.addBar({
  size: 3, // 3 lines height
  template: ({progress}) => [
    `<cyan>=====================</cyan>`,
    `<cyan>Progress: <yellow>${progress.toFixed(2)}%</yellow></cyan>`,
    `<cyan>=====================</cyan>`
  ]
});

let progress = 0;
progressBar.update({progress});
RConsole.print('We can print some message');
RConsole.print('But bottomBar will be displayed always at the bottom');


let memoryHandle = setInterval(() => {
  memoryUsage.update(process.memoryUsage().heapUsed) // Displays current heap usage
}, 500);


// Emulates progress
let handle = setInterval(() => {
  progress += Math.random() * 20;
  if (progress >= 100) {
    progress = 100;
    clearInterval(handle);
    clearInterval(memoryHandle)
  }
  progressBar.update({progress}) // update bottomBar value. All previously printed messages will stay on screen
}, 500);

API

RConsole.print(coloredMessage)

Displays message in the console

coloredMessage

Type: string

String to print. May contain color tags:

• <red>
• <green>
• <yellow>
• <blue>
• <magenta>
• <cyan>
• <white>
• <black>

All text inside tags will be colored.

RConsole.addBar(config)

ReturnType: Bar

Adds a sticky bottom bar at the bottom of console. Bar will not be displayed automatically. To display bar see Bar.update() method.

config

size

Type: number

Number of lines that bar takes.

template

Type: function

ReturnType: coloredString[]

Function that will be invoked when Bar:update() is called. All parameters of update method will be passed to template. The result must be an array of size strings.

Bar.update(...values)

Displays/Updates the bar with new values.

values

Type: ...any

Values that will be passed to template callback.