neat-log

[![npm][npm-image]][npm-url]
[![travis][travis-image]][travis-url]
[![standard][standard-image]][standard-url]

A neat logger for command line tools, inspired by Choo! I've heard so much about how awesome front-end javascript has gotten, I wanted to bring some of that magic to command line applications. Used in the Dat command line tool.

* Use easy-to-read strings to create console outputs.
* Automatically diff template output with existing console (via diffy) (pretty much React for your terminal).
* Update console output in any order with event based output.
* Handle command line input via neat-input.
* Pretty neat!

$3

Each neat logger has two components: a view and functions that modify state and emit events.

``js
var neatLog = require('neat-log')
var output = require('neat-log/output')

var neat = neatLog(view)
neat.use(countTheSeconds)

function view (state) {
// This gets printed to the console! Wow. So neat.
return output(
Hello World!
I've been running for ${state.seconds} second${state.seconds === 1 ? '' : 's'}.
)
}

function countTheSeconds (state, bus) {
state.seconds = 0
setInterval(function () {
state.seconds++
bus.emit('render')
}, 1000)
bus.emit('render')
}
`

This example will print to the console:

`
Hello world!
I've been running for 0 seconds.
`

And update every second!

More examples:

* dat - full command line application with multiple views, components, etc.
* cabal - p2p chat application.
* count-files - simple example with a single view and use function.
* basic examples

$3

Neat-log works great with components, just like Choo!

* Task lister: task runner with pretty output. Used in dat-doctor.
* Spinner: pretty spinner for the cli.
* Text Blit: Draw lines of text onto other lines of text.

You can use string-based components too! Check out diff components for more.

Install

`
npm install neat-log
`

API

Heavily inspired by Choo! If you get confused here, check docs there because they are much nicer =).

$3

* views is a single function or array of functions that return string(s) to output to the console. views are passed the state as the first argument.
* opts.logspeed (default 250ms) - throttles how often output is rendered.
* opts.quiet - shhhh.... do not print anything
* opts.state - pass in initial state

$3

Use a function (state, bus) to change state and emit events via the bus. You can call bus.emit() to emit a new event and bus.on() to listen. Emitter is an instance of nanobus.

bus also has some special functions/events:

#### bus.render()

Cause an immediate render (normally it'd be throttled). This is helpful to do before exiting.

#### bus.on('exit')

Handle exit from process.on('SIGINT')`. Useful for rendering exit messages, etc. If no handler is provided, process will exit.

$3

For an immediate render. Helpful outside of a use function.

$3

Get a function to make your template literals nicer. Removes spaces and stuff™.

Licensing

This package is free to use for noncommercial purposes and for commercial purposes during a trial period under the terms of the Prosperity Public License.

Licenses for long-term commercial use are available via licensezero.com.


[npm-image]: https://img.shields.io/npm/v/neat-log.svg?style=flat-square
[npm-url]: https://www.npmjs.com/package/neat-log
[travis-image]: https://img.shields.io/travis/joehand/neat-log.svg?style=flat-square
[travis-url]: https://travis-ci.org/joehand/neat-log
[standard-image]: https://img.shields.io/badge/code%20style-standard-brightgreen.svg?style=flat-square
[standard-url]: http://npm.im/standard