index.js

#!/usr/bin/env node

const fs = require('fs');
const path = require('path');

const program = require('commander');
const recursive = require("recursive-readdir");
const targz = require('targz');
const tmp = require('tmp');
const YAML = require('yaml');
const ignore = require('ignore');

function toUnityPosixPath(pathStr) {
	let result = pathStr.split(path.sep).join(path.posix.sep);

	debug(`toPosixPath: ${result}`);

	if (result.indexOf("Assets/") !== 0) {
		result = "Assets/" + result;
	}

	return result;
}

let directory = null;

program
	.arguments('<directory>')
	.option('-o, --output <output filename>', 'The output package name', 'Assets.unitypackage')
	.option('--overwrite', 'Overwrite output file if exists', false)
	.option('-x, --exclude <filter>', 'Exclude files/folders using comma separated string (uses .gitignore spec)')
	.option('-p, --prepend <directory>', 'Prepend directory to \'pathname\' in asset package')
	.option('-d, --debug', 'Debug script', false)
	.action(function (dir) {
		directory = dir || ".";
	})
	.parse(process.argv);

directory = directory || ".";

let ig = ignore();
if (program.exclude) {
	let exclude = program.exclude;
	ig = ignore().add(exclude.split(',').filter(item => item.trim() !== ''));
}

let debug = function () {
	if (program.debug) {
		console.log(...arguments);
	}
}

if (fs.existsSync(program.output)) {
	if (program.overwrite) {
		fs.unlinkSync(program.output);
	} else {
		console.log(`Output file '${program.output}' exists. Use --overwrite to overwrite existing file.`);
		process.exit(1);
	}
}

let ignoreFunction = function (file, stats) {
	let filePath = path.relative(directory, file);
	let ignored = ig.ignores(filePath);
	if (ignored) {
		debug("Excluding file", file);
	}

	return ignored;
}

recursive(directory, [ignoreFunction], function (err, files) {
	if (err) {
		console.log("Asset packaging failed", err);
		process.exit(1);
	}

	let onDiskFiles = {};
	files.forEach(file => {
		if (file.endsWith('.meta')) {
			let original = file.substr(0, file.length - 5);
			let currentItems = onDiskFiles[original];
			let items = { ...currentItems, meta: file };
			onDiskFiles[original] = items;
		} else {
			let currentItems = onDiskFiles[file];
			let items = { ...currentItems, asset: file };
			onDiskFiles[file] = items;
		}
	});

	let temp = tmp.dirSync();
	let tempDirectory = temp.name;
	debug(`Working temp directory is ${tempDirectory}.`);

	for (var file in onDiskFiles) {
		let data = onDiskFiles[file];

		if (!data.meta) {
			debug(`Skipping ${file}. Not .meta file found.`);
			continue;
		}

		const metaFile = fs.readFileSync(data.meta, 'utf8')
		let meta = YAML.parse(metaFile);
		let itemDirectory = path.join(tempDirectory, meta.guid);
		fs.mkdirSync(itemDirectory);

		debug(`\n\n${JSON.stringify(meta)}\n\n`);

		let fullPath = [];
		if (program.prepend) {
			fullPath.push(program.prepend);
		}
		fullPath.push(path.relative(directory, file));
		let filePath = toUnityPosixPath(path.join(...fullPath));
		let pathname = path.join(itemDirectory, 'pathname').replace();
		debug(`Writing ${filePath} to ${pathname}`);
		fs.writeFileSync(pathname, filePath);

		let assetMeta = path.join(itemDirectory, 'asset.meta');
		debug(`Meta Copying '${data.meta}' to ${assetMeta}`);
		fs.copyFileSync(data.meta, assetMeta);

		if (data.asset) {
			let asset = path.join(itemDirectory, 'asset');
			debug(`Copying '${data.asset}' to ${asset}`);
			fs.copyFileSync(data.asset, asset);
		} else {
			debug(`No asset to copy for ${file}`);
		}
	}

	targz.compress({ src: tempDirectory, dest: program.output }, function (err) {
		if (err) {
			console.log("Asset packaging failed", err);
			process.exit(1);
		} else {
			console.log(`Asset package '${program.output}' created successfully.`);
		}
	});
});