cli.js

#!/usr/bin/env node
'use strict';
const brightness = require('brightness');
const meow = require('meow');
const progressControl = require('progress-control');
const chalk = require('chalk');
const cliCursor = require('cli-cursor');
const firstRun = require('first-run');
const indentString = require('indent-string');

const cli = meow(`
	Example
	  $ brightness
	  $ brightness 0.8
`);

const updateBar = (val, bar) => brightness.set(val).then(() => {
	const str = `${(val * 100)}%`;
	const maxLength = 4;

	bar.update(val, {val: indentString(str, maxLength - str.length, ' ')});
});

const getBar = (val, text) => {
	const bar = progressControl(text, {total: 10}, {
		up() {
			val = Math.min(Math.round((val + 0.1) * 10) / 10, 1);
			updateBar(val, bar);
		},
		down() {
			val = Math.max(Math.round((val - 0.1) * 10) / 10, 0);
			updateBar(val, bar);
		}
	});

	return bar;
};

const main = val => {
	if (!process.stdout.isTTY) {
		console.log(val);
		return;
	}

	val = Math.round((val) * 10) / 10;

	let text = '[:bar] :val';

	if (firstRun()) {
		text += `   ${chalk.dim('Use up/down arrows')}`;
	}

	const bar = getBar(val, text);

	cliCursor.hide();
	updateBar(val, bar);
};

try {
	if (cli.input.length === 0) {
		brightness.get().then(val => main(val));
	} else {
		brightness.set(parseFloat(cli.input[0], 10));
	}
} catch (err) {
	console.error(err.message);
	process.exit(1);
}