Prevent Access-Control-Expose-Headers header to be overwritten

[carlosanjos]

I tried using a middleware to create a new header to be consumed by a JavaScript web application, but I can't use the custom header because Access-Control-Expose-Headers won't allow it. So I decided to created the following middleware.

module.exports = (req, res, next) => {
    res.header('X-Hello', 'World');
    res.append('Access-Control-Expose-Headers', 'X-Hello');
    next();
}

But if I try the consume the API using using any pagination item, like _page Access-Control-Expose-Headers is overwritten by Access-Control-Expose-Headers: X-Total-Count, Link
I also tried to create a custom server, but I got the same result

const jsonServer = require('json-server');
const server = jsonServer.create();
const router = jsonServer.router('./api/projects.json');
const middlewares = jsonServer.defaults();

server.use(middlewares);

server.use((req, res, next) => {
    res.setHeader(
        'X-Hello',
         'World'
    );

    res.setHeader(
        'Access-Control-Expose-Headers',
        'X-Hello',
    )

    next();
});


server.use(router);
server.listen(4000, () => {
    console.log('JSON Server is running');
});

This change will prevent the aforementioned header to be overwritten.