How to turn bun.js async call into sync?

I need to turn async function running in the bun.js engine into sync one.

Reason: large codebase depends on existing sync implementation of the getData function. It needs to be evolved and utilise some async features, but its signature should be kept sync for backward compatibility.

It’s impossible to do with JS. The way I see how to implement it:

• The main JS process starts WebWorker in background that listen on net port.
• The getData uses execSync to call curl to send request to WebWorker port, to call async function getDataNewWay and get back the response.

Probably the simplest solution, but the overhead is large.

Wonder if there’s better way? Like:

• Using unix named pipes and readFileSync/writeFileSync?
• Using bun ffi to call some C/C++ system library, to do the networking call (same as with execSync and curl, but more efficient)?
• There are advanced C node.js extensions like fibers that do exactly that, but I would like to avoid heavily altering the JS engine, as it may cause unexpected bugs.
• XMLHttpRequest in sync mode (seems like it’s not supported in bun)?

Example:

// The API `getData` that should be kept backward compatible
function getData(key: string): string {
  if (key == 'old_key') return getDataOldWay(key)
  return callSync('getDataNewWay', [key])
}

// The possible implementation
function getDataOldWay(key: string): string {
  return 'some data'
}
async function getDataNewWay(key: string): Promise<string> {
  return 'some data'
}
globalThis.getDataNewWay = getDataNewWay

function callSync<T>(fname: string, args: any[]): any {
  const code = `await globalThis.${fname}(...${JSON.stringify(args)})`
  return child_process.execSync(`http://localhost:3000/eval=${code}`).toString()
}