TypeORM ormconfig.json loader

ormconfig-loader.js

const glob = require('glob');

const jsValidJson = (value) => JSON.stringify(value)
  .replace(/\u2028/g, '\\u2028')
  .replace(/\u2029/g, '\\u2029');

module.exports = function(source) {
  const obj = typeof source === 'string' ? JSON.parse(source) : source;

  // loadFileClasses is copied from TypeORM, MIT License, Copyright (c) 2015-2016 Yakdu. http://typeorm.github.io
  // https://github.com/typeorm/typeorm/blob/master/src/util/DirectoryExportedClassesLoader.ts#L9
  return `
  var typeorm = require('typeorm');
  function loadFileClasses(exported, allLoaded) {
    if (typeof exported === "function" || exported instanceof typeorm.EntitySchema) {
        allLoaded.push(exported);
    }
    else if (Array.isArray(exported)) {
        exported.forEach(function (i) { return loadFileClasses(i, allLoaded); });
    }
    else if (typeof exported === "object") {
        Object.keys(exported).forEach(function (key) { return loadFileClasses(exported[key], allLoaded); });
    }
    return allLoaded;
  }

  module.exports = { ${ Object.keys(obj).map(key => {
    let value = obj[key];
    let stringified = false;

    if (key === 'entities') {
      let array = [];
      value.forEach(pattern => glob.sync(pattern).forEach(entity => {
        this.addDependency(entity);
        array.push(`require(${jsValidJson(entity)})`);
      }))

      value = `loadFileClasses([${array.join(', ')}], [])`;
      stringified = true;
    }

    if (!stringified) {
      value = jsValidJson(value);
    }

    return `${jsValidJson(key)}: ${value}`
  }).join(', ') } };`;
}

webpack.config.js

module.exports = {
  module: {
    rules: [{
      test: /ormconfig\.json/,
      type: 'javascript/auto',
      loader: path.resolve('ormconfig-loader.js')
    }]
  }
  // ...
}