diffy

A tiny framework for building diff based interactive command line tools.

npm install diffy

Basically React, but in the terminal powered by ansi-diff and neat-input.

Usage

var diffy = require('diffy')()
var trim = require('diffy/trim')

diffy.render(function () {
  return trim(`
    Hello user. The time is:
      ${new Date()}
    That is all for now
  `)
})

// re-render every 1s
setInterval(() => diffy.render(), 1000)

You can also use diffy to query input from a user

var diffy = require('diffy')()
var trim = require('diffy/trim')
var input = require('diffy/input')({style: style})
var names = []

input.on('update', () => diffy.render())
input.on('enter', (line) => names.push(line))

diffy.render(function () {
  return trim(`
    Enter your name: ${input.line()}
    List of names: ${names.join(', ')}
  `)
})

function style (start, cursor, end) {
  return start + '[' + (cursor || ' ') + ']' + end
}

See the examples folder for more.

API

var diffy = require('diffy')([options])

Make a new diffy instance. Writes to stdout.

Options include:

{
  fullscreen: true // overtake the terminal like vim/less does
}

Note that if you use fullscreen: true, the terminal will be restored on exit, even if your program crashes.

diffy.render([function])

Trigger a render and/or update the default render function. A render function should simply return a string containing the output you wish to display and then diffy will make sure to only print the diff.

diffy.width

Property containing the width of the terminal.

diffy.height

Property containing the height of the terminal.

diffy.on('resize')

Emitted when the terminal is resized. Triggers a render as well.

diffy.on('render')

Emitted just before a render happens.

var input = require('diffy/input')()

Get a neat-input instance. Use this if you want to accept interactive input.

var trim = require('diffy/trim')

Helper function that trims and removes the indentation of a multiline string. Useful if you have a render function that returns an indented string like in the above example.

var trim = require('diffy/trim+newline')

Helper function that trims but adds a newline at the end

Components

With diffy, components are just strings you compose together to form your application. A bunch of modules already exists for this pattern, providing useful features.

• watson/menu-string - Generate a menu with selectable menu items as a string.
• watson/progress-string - Generate a CLI progress bar as a string that you can then output in any way you like.
• mafintosh/scrollable-string - Generate a diff friendly string that is bounded by a configurable scroll box.

Credits

Thank you to @Fouad for donating the module name.

License

MIT