build.js

const fs = require("fs");
const path = require("path");
const ncp = require("ncp").ncp;
const formatJSON = require("json-format");
const rimraf = require("rimraf");
const JSZip = require("jszip");
const args = process.argv;
const isFirefox = args.includes("firefox");
const isZip = args.includes("zip");

const chromePath = path.join(__dirname, "chrome");
const firefoxPath = path.join(__dirname, "firefox");
const buildPath = isFirefox ? firefoxPath : chromePath;
const src = path.join(__dirname, "src");
ncp.limit = 16;

// convert callback to promises
const promisify = (fn, args) => {
	return new Promise((resolve, reject) => {
		try {
			args.push((...arg) => resolve(arg));
			fn.apply(this, args);
		} catch (e) {
			reject(e);
		}
	});
};

// remove existing directory
promisify(rimraf, [buildPath])
	.then(() => {
		// make directory
		return promisify(fs.mkdir, [buildPath]);
	})
	.then(() => {
		// copy all files/folders recursively to destination
		return promisify(ncp, [src, buildPath]);
	})
	.then(() => {
		// read manifest.json
		return promisify(fs.readFile, [
			path.join(buildPath, "manifest.json"),
			"utf8"
		]);
	})
	.then(res => {
		// modify JSON if firefox
		if (res[0]) throw Error("unable to read manifest");
		const fileJson = JSON.parse(res[1]);
		if (isFirefox) {
			fileJson.applications = {
				gecko: {
					id: "permissionInspector@web-ext-labs",
					strict_min_version: "55.0"
				}
			};
		}
		return promisify(fs.writeFile, [
			path.join(buildPath, "manifest.json"),
			formatJSON(fileJson)
		]);
	})
	.then(() => {
		// delete chrome/firefox as per build
		const toDelete = path.join(
			buildPath,
			isFirefox ? "chrome.js" : "firefox.js"
		);
		return promisify(fs.unlink, [toDelete]);
	})
	.then(() => {
		// read index.html
		return promisify(fs.readFile, [path.join(buildPath, "index.html"), "utf8"]);
	})
	.then(res => {
		// remove chrome/firefox script as per build
		if (res[0]) throw Error("unable to read index file");
		const lines = res[1].split("\n");
		const matcher = isFirefox ? "chrome" : "firefox";
		const finalArr = lines.filter(l => !l.includes(matcher));
		return promisify(fs.writeFile, [
			path.join(buildPath, "index.html"),
			finalArr.join("\n")
		]);
	}).then(() => {
		return promisify(fs.unlink, [`${buildPath}.zip`])
	})
	.then(() => {
		if (isZip) {
			const zip = new JSZip();
			const build = isFirefox ? "firefox" : "chrome";

			const readAll = function (dir, filelist = []) {
				fs.readdirSync(dir).forEach(function (file) {
					if (fs.statSync(path.join(dir, file)).isDirectory())
						filelist = readAll(path.join(dir, file), filelist);
					else
						filelist.push(path.join(dir, file));
				});
				return filelist;
			};

			readAll(build).forEach(f =>
				zip.file(f.replace(`${build}`, ""), fs.readFileSync(f))
			);

			zip
				.generateNodeStream({ type: "nodebuffer", streamFiles: true })
				.pipe(fs.createWriteStream(`${build}.zip`))
				.on("finish", () => {
					console.log(`${build}.zip written`);
					promisify(rimraf, [buildPath]);
				});
		}
	})
	.catch(e => console.log(`Schaize: ${e}`));