index.js

#!/usr/bin/env node
"use strict";

var cli = require("cli");
var path = require("path");
var open = require("open");
var chalk = require("chalk");
var moment = require("moment");
var quote = require("starwars")();
var spawn = require("cross-spawn-async");
var stream = require("fs").createWriteStream;

/**
 * Chalk styles
 */
var b = chalk.bold;
var g = chalk.green;
var m = chalk.bgMagenta;

/**
 * Spinner text
 */
var spinner = m(b(`“${quote}”`));

/**
 * User information
 *
 * @type {Object}
 */
var user = {
    git: {
        name: require("git-user-name")(),
        email: require("git-user-email")()
    },
    dates: {
        since: moment(18, "DD")
            .subtract(1, "month")
            .format("YYYY-MM-DD"),
        until: moment(18, "DD").format("YYYY-MM-DD")
    },
    home: require("os-homedir")()
};

/**
 * Plugins
 */
cli.enable("catchall");

/**
 * Parses the arguments given options
 */
cli.parse({
    name: ["n", "Your git user", "string"],
    email: ["e", "Your git email", "email"],
    since: ["s", "Date to log from, YYYY-MM-DD", "string", user.dates.since],
    until: ["u", "Date to log to, YYYY-MM-DD", "string", user.dates.until],
    format: ["f", "Git log format", "string", "%h%x09%an%x09%ad%x09%s"],
    open: ["o", "Open file upon creation", "boolean", false],
    dest: ["d", "Where do you want to save the file", "path", user.home]
});

/**
 * Call to main method
 */
cli.main(main);

/**
 * Main method
 *
 * @param  {Array}  args     Arguments array
 * @param  {Object} options  Options object
 */
function main() {
    prepareOptions();
    cli.spinner(spinner);
    var git = spawn("git", command(), { cwd: process.cwd() });
    var log = stream(cli.options.filename);
    // pipe stdout to log stream
    git.stdout.pipe(log);
    // say good-bye!
    git.on("close", onGitClose);
}

/**
 * Stream close handler
 *
 * @param  {code} code Process exit code
 */
function onGitClose(code) {
    switch (code) {
        case 0:
            cli.spinner(spinner, true);
            console.log(g("✔"), `${cli.options.filename}`);
            if (cli.options.open) {
                open(cli.options.filename);
            }
            break;
        case 128:
            cli.spinner(spinner, true);
            throw new Error("Dude, wake up, this is not a GIT repository...");
        default:
            throw new Error(
                "Some weird shit happened, git exited with code: " + code
            );
    }
}

/**
 * Prepares and validates options
 */
function prepareOptions() {
    var opts = cli.options;

    opts.since = moment(opts.since, "YYYY-MM-DD");
    opts.until = moment(opts.until, "YYYY-MM-DD");
    opts.filename = filename();

    [opts.since, opts.until].forEach(date => {
        if (!date.isValid()) {
            throw new Error("Please provide dates in YYYY-MM-DD format.");
        }
    });

    if (!author()) {
        throw new Error(
            "You need to provide --name or --email, or set your git name or email configuration."
        );
    }
    if (opts.until.isBefore(opts.since)) {
        throw new Error(
            'This ain\'t no time machine pal, "until" date must be after "since" date.'
        );
    }
}

/**
 * Prepares the git command before execution
 *
 * @return {String} Prepared command
 */
function command() {
    var opts = cli.options;

    return [
        "log",
        "-p",
        "--all",
        "--no-merges",
        `--since=${opts.since.format()}`,
        `--until=${opts.until.format()}`,
        "--reverse",
        `--author=${author()}`,
        `--pretty=format:"${opts.format}"`
    ];
}

/**
 * Decide what to use for author parameter
 *
 * @return {String}         Git email or name
 */
function author() {
    return (
        cli.options.email || cli.options.name || user.git.email || user.git.name
    );
}

/**
 * Generates a file name with path to OS home dir
 *
 * @return {String} Full path to the file
 */
function filename() {
    var opts = cli.options;
    var since = opts.since.format("YYYY-MM-DD");
    var until = opts.until.format("YYYY-MM-DD");
    var name = [unwrapScope(project()), "samples", since, "to", until]
        .join("-")
        .concat(".txt");

    return path.join(opts.dest, name);
}

/**
 * Find package.json name entry, fallbacks to current folder name
 *
 * @return {String} Project name
 */
function project() {
    try {
        return require(path.join(process.cwd(), "package.json")).name;
    } catch (e) {
        return process
            .cwd()
            .split(path.sep)
            .pop();
    }
}

/**
 * Replaces slash with dash if package is scoped
 *
 * @param {String} name
 * @return {String} Project name
 */
function unwrapScope(name) {
    var isScoped = name.indexOf("@") !== -1;
    return isScoped ? name.replace("/", "-") : name;
}