server.js

const path = require('path');

const sources = {};
const shaderFileRegex = /\.shader\.js$/i;

module.exports.updateShaderSource = function (file, opt) {
  sources[file] = opt;
};

module.exports.isShaderReload = function (deps) {
  return deps.length > 0 && deps.every(dep => shaderFileRegex.test(dep));
};

module.exports.isShaderError = function (err) {
  return err.filename && shaderFileRegex.test(err.filename);
};

module.exports.getErrorEvent = function (error) {
  return {
    event: 'shader-error',
    error: error.message
  };
};

module.exports.getEvent = function (deps, cwd) {
  cwd = cwd || process.cwd();

  // Use the same format as "__filename" in the browser
  const files = deps.map(dep => {
    return path.join(path.sep, path.relative(process.cwd(), dep));
  });

  const updates = getUpdates(files);
  return {
    event: 'shader-reload',
    updates: updates
  };
};

function getUpdates (files) {
  return files.map(file => {
    if (file in sources) {
      return Object.assign({}, sources[file], {
        file
      });
    } else {
      return null;
    }
  }).filter(Boolean);
}