sade/lib/utils.js

const rpad = require('pad-right');

const GAP = 4;
const __ = '  ';
const ALL = '__all__';
const DEF = '__default__';
const NL = '\n';

function format(arr) {
	if (!arr.length) return '';
	let len = maxLen( arr.map(x => x[0]) ) + GAP;
	let join = a => rpad(a[0], len, ' ') + a[1] + (a[2] == null ? '' : `  (default ${a[2]})`);
	return arr.map(join);
}

function maxLen(arr) {
  let c=0, d=0, l=0, i=arr.length;
  if (i) while (i--) {
    d = arr[i].length;
    if (d > c) {
      l = i; c = d;
    }
  }
  return arr[l].length;
}

function noop(s) {
	return s;
}

function section(str, arr, fn) {
	if (!arr || !arr.length) return '';
	let i=0, out='';
	out += (NL + __ + str);
	for (; i < arr.length; i++) {
		out += (NL + __ + __ + fn(arr[i]));
	}
	return out + NL;
}

exports.help = function (bin, tree, key) {
	let out='', cmd=tree[key], pfx=`$ ${bin}`, all=tree[ALL];
	let prefix = s => `${pfx} ${s}`;

	// update ALL & CMD options
	all.options.push(['-h, --help', 'Displays this message']);
	cmd.options = (cmd.options || []).concat(all.options);

	// write options placeholder
	(cmd.options.length > 0) && (cmd.usage += ' [options]');

	// description ~> text only; usage ~> prefixed
	out += section('Description', cmd.describe, noop);
	out += section('Usage', [cmd.usage], prefix);

	if (key === DEF) {
		// General help :: print all non-internal commands & their 1st line of text
		let cmds = Object.keys(tree).filter(k => !/__/.test(k));
		let text = cmds.map(k => [k, (tree[k].describe || [''])[0]]);
		out += section('Available Commands', format(text), noop);

		out += (NL + __ + 'For more info, run any command with the `--help` flag');
		cmds.slice(0, 2).forEach(k => {
			out += (NL + __ + __ + `${pfx} ${k} --help`);
		});
		out += NL;
	}

	out += section('Options', format(cmd.options), noop);
	out += section('Examples', cmd.examples.map(prefix), noop);

	return out;
}

exports.error = function (bin, str, num=1) {
	let out = section('ERROR', [str], noop);
	out += (NL + __ + `Run \`$ ${bin} --help\` for more info.` + NL);
	console.error(out);
	process.exit(num);
}

// Strips leading `-|--` & extra space(s)
exports.parse = function (str) {
	return (str || '').split(/^-{1,2}|,|\s+-{1,2}|\s+/).filter(Boolean);
}

// @see https://stackoverflow.com/a/18914855/3577474
exports.sentences = function (str) {
	return (str || '').replace(/([.?!])\s*(?=[A-Z])/g, '$1|').split('|');
}