Git post-checkout hook that notifies when dev should run commands

build-check.js

/**
 * ------------------------------------------------------------------
 * Get notified when you should run some commands when switching
 * between branches.
 *
 * Usage:
 * Adjust `checkChange` function calls by putting a command as
 * the second argument, and then a list of file/folder paths
 * that you want to monitor for changes as following arguments.
 *
 * Installation:
 * 1. Install husky and chalk
 *    yarn add --dev husky chalk
 * 2. Add post-checkout hook in package.json
 *    "husky": {
 *      "hooks": {
 *        "post-checkout": "node build-check.js",
 *      }
 *    },
 * ------------------------------------------------------------------
 */

const { exec } = require('child_process');
const chalk = require('chalk');

const argParams = process.argv;
const gitParams = process.env.GIT_PARAMS
    ? process.env.GIT_PARAMS.split(' ')
    : [];

const prev = getCommitHash(argParams[2], gitParams[0], 'ORIG_HEAD');
const head = getCommitHash(argParams[3], gitParams[1], 'HEAD');

const commandsToRun = [];

exec(
    `git diff-tree -r --name-only --no-commit-id ${prev} ${head}`,
    (error, stdout) => {
        if (error && error.message.includes('ambiguous argument')) {
            return;
        }

        handleError(error);

        if (!stdout) {
            return;
        }

        checkChange(stdout, 'composer install', 'composer.json', 'composer.lock');
        checkChange(stdout, 'yarn install', 'package.json', 'yarn.lock');
        checkChange(stdout, 'yarn build', 'resources/js', 'resources/sass');
        checkChange(stdout, 'php artisan migrate', 'database/migrations');

        notifyChanges();
    },
);

function getCommitHash() {
    return Array.prototype.find.call(arguments, arg => {
        if (typeof arg === 'string' && arg.length > 1) {
            return true;
        }
    });
}

function handleError(error) {
    if (error) {
        console.error(`${chalk.red('exec error')}: ${error}`);
        process.exit(1);
    }
}

function checkChange(changes, command, ...paths) {
    for (const path of paths) {
        if (changes.includes(path) && commandsToRun.indexOf(command) === -1) {
            commandsToRun.push(command);
            break;
        }
    }
}

function notifyChanges() {
    if (commandsToRun.length === 0) {
        return;
    }

    exec('git config user.name', (error, stdout) => {
        handleError(error);

        const hey = stdout ? stdout.split(' ')[0].trim() : 'Hey';
        const log = console.log;

        log();
        log(`${chalk.black.bgYellow(hey)}${chalk.yellow(', you probably should run:')}`);

        for (const command of commandsToRun) {
            log(chalk.green(command));
        }

        log();
    });
}