tag-branch.js

var shell = require('shelljs');

if (! shell.which('git')) {
	shell.echo('Sorry, this script requires git');
	shell.exit(1);
}

var branchName = shell.exec("git rev-parse --abbrev-ref HEAD", {silent:true}).replace(/\n/g, "");
var branchVersion = parseVersion(branchName);
if (! branchVersion) {
	shell.echo("Branch name '" + branchName + "' does not follow expected pattern release/v#.#.x");
	shell.exit(1);
}

var versionTags = shell.exec("git tag", {silent:true})
	.split("\n")
	.map(parseVersion)
	.filter(function(v) {
		return v && v.major == branchVersion.major && v.minor == branchVersion.minor;
	})
	.sort(function(a, b){
		// Sort in descending order
		return b.patch - a.patch;
	})
	;

var latestVersion = versionTags[0];
var nextTag;

if (latestVersion) {
	nextTag = "v" + latestVersion.major + "." + latestVersion.minor + "." + (latestVersion.patch + 1);
} else {
	nextTag = "v" + branchVersion.major + "." + branchVersion.minor + "." + 0;
}

shell.echo("Pulling changes for this branch");
shell.exec("git pull");

shell.echo("Tagging the branch");
shell.exec("git tag '" + nextTag + "' -m 'Version " + nextTag + "'");

shell.echo("Pushing the branch");
shell.exec("git push --follow-tags");


function parseVersion(
	verStr
) {
	var parts = verStr.match(/(?:.*\/)?v?(\d+)\.(\d+)\.(\d+|x)/);

	return parts && {
		major: parseInt(parts[1]),
		minor: parseInt(parts[2]),
		patch: parts[3] == "x" ? null : parseInt(parts[3])
	};
}