import { evaluate } from 'mathjs';

function done(data: string): void {
  if (process && process.send) {
    process.send(data);
  }
}

process.once('message', (msg) => {
  let expr = msg.toString();

  if (!expr) {
    return done('null');
  }
  if (expr.indexOf('=') === expr.length - 1) {
    expr = expr.substring(0, expr.length - 1);
  }

  expr = expr.replace(/π/g, 'pi');
  let result = 'null';

  try {
    result = evaluate(expr);
  } catch (e) {
    return done(e.message);
  }

  return done(result.toString());
});