@tdb/util.server/src/express.ts

import * as express from 'express';
const IS_PRODUCTION = process.env.NODE_ENV === 'production';

interface IErrorStack {
  message: string;
  stack: string[];
}

/**
 * Turns an Error stack into a friendlier JSON value.
 */
function formatErrorStack(stack: string = ''): IErrorStack {
  const lines = stack.split('\n');
  const message = lines[0];
  lines.shift();
  return {
    message,
    stack: lines.map(line => line.trim()),
  };
}

/**
 * Sends an HTTP error to the client, with full stack details
 * if running locally in development.
 */
export function sendError(code: number, res: express.Response, err: Error) {
  const error = IS_PRODUCTION ? err.message : formatErrorStack(err.stack);
  res.status(code).send({
    status: code,
    error,
  });
}