Top-level await support for TypeScript REPL

repl.js

// ... by wrapping the executed statement in an async IIFE

const repl = require("repl")

const wrapInAsync = (cmd) => {
  if (!cmd.trim()) return ""

  return `;(async () => {
    return (
      ${cmd}
    )
  })()`
}

const replInstance = repl.start()
const defaultEval = replInstance.eval

replInstance.eval = (cmd, context, filename, callback) => {
  defaultEval(wrapInAsync(cmd), context, filename, async (error, result) => {
    if (error) return callback(error)

    try {
      callback(null, await Promise.resolve(result))
    } catch (e) {
      callback(e)
    }
  })
}

Or just use node --experimental-repl-await -r ts-node/register directly instead.