readme.md

mkdir test262-transformers
export TRANSFORMERS=$PWD/test262-transformers
cd test262-transformers
npm init -y
npm install --save @babel/core @babel/preset-env
touch spec.js 

Copy the contents to spec.js into your local spec.js

spec.js

const babel = require("@babel/core");
const options = {
  cwd: __dirname,
  presets: [
    [
      "@babel/preset-env",
      {
        spec: true
      }
    ]
  ]
};

module.exports = function(code) {
  let c = babel.transform(code, options).code;
  console.log(c);
  return c;
};