Smaller es6 bundler possible

bundler.js

const fs = require("fs");
const path = require("path");
const parser = require("@babel/parser");
const traverse = require("@babel/traverse").default;
const babel = require("@babel/core");
const resolve = require("resolve").sync;

let ID = -1;

function createModuleInfo(filePath) {
  const content = fs.readFileSync(filePath, "utf-8");
  const ast = parser.parse(content, {
    sourceType: 'module'
  })
  const deps = []
  traverse(ast, {
    ImportDeclaration: ({ node }) => {
      deps.push(node.source.value)
    }
  })
  ID++
  const { code } = babel.transformFromAstSync(ast, null, {
    presets: ["@babel/preset-env"]
  })
  return {
    id: ID,
    filePath,
    deps,
    code
  }
}

function createDependencyGraph(entry) {
  const entryInfo = createModuleInfo(entry)
  const graphArr = [entryInfo]
  for (const module of graphArr) {
    module.map = {}
    module.deps.forEach(depPath => {
      const baseDir = path.dirname(module.filePath)
      const moduleDepPath = resolve(depPath, { baseDir })
      const moduleInfo = createModuleInfo(moduleDepPath)
      graphArr.push(moduleInfo)
      module.map[depPath] = moduleInfo.id
    })
  }
  return graphArr
}

function pack(graph) {
  const moduleArgArr = graph.map(module => {
    return `${module.id}:  {
      factory: (exports, require) => {
        ${module.code}
      },
      map:  ${JSON.stringify(module.map)}
    }`
  })
  const iifeBundler = `(function(modules){
    const require = id => {
      const { factory, map } = modules[id]
      const localRequire = requireDeclarationName => require(map[requireDeclarationName])
      const module = { exports:{}}
      factory(module.exports, localRequire)
      return module.exports
    }
    require(0)
  })({${moduleArgArr.join()}})`
  return iifeBundler
}

const graph = createDependencyGraph("./entry.js");
const bundle = pack(graph);

console.log(bundle); // copy code and paste it into browser