live-prompt

Simple console with history and redux data flow.

Contents

• Description
• Install
• Features
• Getting Started
• Usage
• Example
• History Navigation
• Thanks

Description

This is a Node console built in with redux architecture.

Install

live-prompt can be installed via npm.

npm install live-prompt

Features

• It remembers your commands and you can navigate around them with the arrow keys.

Getting Started

import livePrompt from 'live-prompt';

const options = {...},
  prompt = livePrompt(options);

prompt.start();

prompt.log('Hey!!');

prompt.stop();

Usage

Options

Default options:

options = {
  stdin = process.stdin,
  stdout = process.stdout,
  middleware = undefined,
  prompt = 'live-prompt:$ ',
  bye = 'see you soon!',
  onCtrlC = undefined,
  encoding = 'utf8'
}

• @param {Object} [options.stdin] Readable stream.
• @param {Object} [options.stdout] Writable stream.
• @param {Function} [options.middleware] Redux middleware function.
• @param {String} [options.prompt] Prompt.
• @param {Object} [options.bye] Final greeting.
• @param {Function} [options.onCtrlC] Callback to be called when ctrl-c is pressed.
• @param {String} [options.encoding] Stdin encoding.

Prompt Object

livePrompt() returns an object with the next methods.

{
  start () {},
  stop () {},
  log (txt) {}
}

Start: sets stdin raw mode true, sets the encoding and subscribes for 'keypress' events.

Stop: unsubscribes stdin from 'keypress' events.

Log: logs txt to the stdout without loosing your command.

Middleware function

This is a common redux middleware function:

middleware = store => next => action => {
  ...
  return next(action);
}

Actions:

Commit is dispatched when you hit return.

{type: 'commit', data: 'command...'}

Prev is dispatched when you hit up arrow key.

{type: 'prev'}

Next is dispatched when you hit down arrow key.

{type: 'next'}

Left is dispatched when you hit left arrow key.

{type: 'left'}

Right is dispatched when you hit right arrow key.

{type: 'right'}

Cancel is dispatched when you hit ESC key.

{type: 'cancel'}

Backspace is dispatched when you hit backspace key.

{type: 'backspace'}

Any other key will be dispatched as chunk.

{type: 'chunk', data: 'chunk...'}

Data Tree Structure

This is the data tree of the state.

{
  history: {
    commands: [...], // array of committed commands.
    index: 0, // current index of the commands array. 
  },
  present: {
    buffer: '...', // it is the current command you are editing/navigating.
    current: '...', // keeps your last input while you are navigating around the history.
    cursor: 0, // current cursor position in buffer.
  }
}

Attention: The value of index being equal to the count of commands means that we are editing the present command.

Example

This example will record every committed command to 'commands.txt' and will log the date every 1 minute.

import livePrompt from 'live-prompt';
import fs from 'fs';

const commands = fs.createWriteStream('./commands.txt'),
  middleware = store => next => action => {
    if (action.type === 'commit') {
      commands.write(action.data);
    }
    return next(action);
  },
  prompt = livePrompt({middleware});

prompt.start();

setInterval(() => {
  prompt.log('[date]: ' + new Date());
}, 60000);

History Navigation

• Navigate through your commands with up and down arrow keys.
• Cancel edit mode hitting ESC once.
• Go back to the last command hitting ESC twice.

Thanks

• Eric Eliott
• redux
• immutable-js
• keypress