@babel/plugin-transform-regenerator

function* a() {
  yield 1;
}

var _marked = [a].map(regeneratorRuntime.mark);

function a() {
  return regeneratorRuntime.wrap(
    function a$(_context) {
      while (1) {
        switch ((_context.prev = _context.next)) {
          case 0:
            _context.next = 2;
            return 1;

          case 2:
          case "end":
            return _context.stop();
        }
      }
    },
    _marked[0],
    this
  );
}

{
  "plugins": ["@babel/plugin-transform-regenerator"]
}

{
  "plugins": [
    [
      "@babel/plugin-transform-regenerator",
      {
        "asyncGenerators": false,
        "generators": false,
        "async": false
      }
    ]
  ]
}

babel --plugins @babel/plugin-transform-regenerator script.js

require("@babel/core").transformSync("code", {
  plugins: ["@babel/plugin-transform-regenerator"],
});