git commit message prepare script (current branch prefix, git-mob support)

prepare-commit-msg.js

#!/usr/bin/env node
let { exec, execSync } = require('child_process'),
    fs = require('fs');
const { stdout } = require('process');

const commitMessage = process.argv[2];
// expect .git/COMMIT_EDITMSG
if (/COMMIT_EDITMSG/g.test(commitMessage)) {
    // opens .git/COMMIT_EDITMSG
    let contents = fs.readFileSync(commitMessage) || '';

    if (process.env.GIT_COMMIT_MSG_PREFIX_WITH_BRANCH_NAME) {
        let current_branch = execSync("git branch --show-current").toString().trim()
        if (!contents.toString().startsWith(current_branch)) {
            contents = current_branch + ' ' + contents
        }
    }

    let mobbers = execSync("git mob-print").toString().trim()
    if (mobbers && contents.indexOf(mobbers) !== -1) {
        const commentPos = contents.indexOf('# ');
        const gitMessage = contents.slice(0, commentPos);
        const gitComments = contents.slice(commentPos)

        contents = gitMessage + mobbers + gitComments
    }

    fs.writeFileSync(commitMessage, contents);
    process.exit(0);
}