Proxy an xhr request by using sapper, polka and http-proxy-middleware

server.js

import sirv from 'sirv';
import polka from 'polka';
import compression from 'compression';
import { createProxyMiddleware } from 'http-proxy-middleware';
import * as sapper from '@sapper/server';

const { PORT, NODE_ENV } = process.env;
const dev = NODE_ENV === 'development';

const server = polka();

// Request is sent to /api/*
server.use("/api", createProxyMiddleware({
  target: 'https://example.com',
  changeOrigin: true,
  pathRewrite: {
    '^/api': '/', // remove base path since we need to drop "api" from the path
  },
}));

server // You can also use Express
  .use(
    compression({ threshold: 0 }),
    sirv('static', { dev }),
    sapper.middleware()
  )
  .listen(PORT, err => {
    if (err) console.log('error', err);
  });