parcel-bundler/src/packagers/Packager.js

<p align="center"> <a href="https://parceljs.org/" target="_blank"> <img alt="Parcel" src="https://user-images.githubusercontent.com/19409/31321658-f6aed0f2-ac3d-11e7-8100-1587e676e0ec.png" width="749"> </a> </p>

const fs = require('fs');
const promisify = require('../utils/promisify');

class Packager {
  constructor(bundle, bundler) {
    this.bundle = bundle;
    this.bundler = bundler;
    this.options = bundler.options;
    this.setup();
  }

  setup() {
    this.dest = fs.createWriteStream(this.bundle.name);
    this.dest.write = promisify(this.dest.write.bind(this.dest));
    this.dest.end = promisify(this.dest.end.bind(this.dest));
  }

  async start() {}

  // eslint-disable-next-line no-unused-vars
  async addAsset(asset) {
    throw new Error('Must be implemented by subclasses');
  }

  async end() {
    await this.dest.end();
  }
}

module.exports = Packager;