a project repl

repl.js

const babel = require('babel-core');
const vm = require('vm');
const repl = require('repl');

let context = repl.start({ eval: evaluate }).context;

// Autorequire all models so that they're available by name in the repl.
const models = require('../server/models');
for (let name in models) {
  context[name] = models[name];
}

const RESULT_SYMBOL = '__eval_res';

function evaluate(cmd, context, filename, callback) {
  context = vm.createContext(context);
  if (cmd.match(/await/)) {
    let assign = null;
    if (cmd.match(/\=/)) {
      let parts = cmd.split('=');
      assign = parts[0];
      cmd = parts.slice(1).join('=');
    }

    cmd = '(async function() { return ' + cmd + '})()';

    try {
      cmd = compile(cmd);
    } catch (e) {
      callback(new repl.Recoverable());
      return;
    }

    let res;
    try {
      res = vm.runInContext(cmd, context);
    } catch (e) {
      callback(e);
      return;
    }

    res.then(
      r => {
        context[RESULT_SYMBOL] = r;
        if (assign) {
          simpleEval(assign + ' = ' + RESULT_SYMBOL, context, filename, callback);
        } else {
          callback(null, r);
        }
      },
      (e) => callback(e)
    );
    return;
  }

  simpleEval(cmd, context, filename, callback);
}

function simpleEval(cmd, context, filename, callback) {
  try {
    cmd = compile(cmd);
  } catch (e) {
    callback(new repl.Recoverable());

    return;
  }

  try {
    callback(null, vm.runInContext(cmd, context));
  } catch (e) {
    callback(e);
    return;
  }
}

function compile(cmd) {
  return babel.transform(cmd, {
    sourceType: 'script',
    blacklist: ['strict'],
  }).code;
}