Angular Devkit like HTTP Proxy for Nx @nrwl/web:file-server

http-proxy.ts

import * as express from 'express';
import { join } from 'path';
import { getProxyConfig } from './webpack-dev-server-proxy-conf';

function error(message: string): never {
  throw new Error(message);
}

const proxyConfigPath = process.argv[2] || error('Please specify proxy config path as argument.');

const createProxyMiddleware = require('http-proxy-middleware');

const app = express();

const config = getProxyConfig(require(join(process.cwd(), proxyConfigPath)));
config.forEach((item) => app.use(item.context, createProxyMiddleware(item.context, item)));

app.listen(3000);

webpack-dev-server-proxy-conf.ts

// Copied from in order to mimic webpack-dev-server proxy config handling
// https://github.com/webpack/webpack-dev-server/blob/master/lib/Server.js#L1379

export interface ProxyConfigItem {
  readonly context: string;
  readonly target: string;
  readonly secure?: boolean;
  readonly changeOrigin?: boolean;
  readonly pathRewrite?: {
    [k: string]: string;
  };
}

export function getProxyConfig(proxyConfig: any): ProxyConfigItem[] {
  return Object.keys(proxyConfig).map(
    /**
     * @param {string} context
     * @returns {HttpProxyMiddlewareOptions}
     */
    (context) => {
      let proxyOptions;
      // For backwards compatibility reasons.
      const correctedContext = context.replace(/^\*$/, '**').replace(/\/\*$/, '');

      if (typeof (/** @type {ProxyConfigMap} */ proxyConfig[context]) === 'string') {
        proxyOptions = {
          context: correctedContext,
          target:
            /** @type {ProxyConfigMap} */
            proxyConfig[context]
        };
      } else {
        proxyOptions = {
          // @ts-ignore
          .../** @type {ProxyConfigMap} */ proxyConfig[context]
        };
        proxyOptions.context = correctedContext;
      }

      return proxyOptions;
    }
  );
}