如何在Express JS中使用多个Http Header（同名）

Question

My Php Code can be send two headers with same name, in php second parameter is for replace or override. but in ExpressJS res.header is not like php code PHP Code:

header("Link: <http://$prefetch_next_img>; rel=prefetch",false); 
header("Link: <http://$prefetch_next_img2>; rel=prefetch",false);  

http://us2.php.net/manual/en/function.header.php

ExpressJS(NodeJS) :

res.header('Link','Fake Value');
res.header('Link','Only Send it'); // previous header replaced

Answer 1

Ultimately, you'll need to pass an array to set multiple values for the same header

res.header('Set-Cookie', ['foo', 'bar']);

Looking at response library for express we can see the following examples:

/**
 * Set header `field` to `val`, or pass
 * an object of header fields.
 *
 * Examples:
 *
 *    res.set('Foo', ['bar', 'baz']);
 *    res.set('Accept', 'application/json');
 *    res.set({ Accept: 'text/plain', 'X-API-Key': 'tobi' });
 *
 * Aliased as `res.header()`.
 *
 * @param {String|Object} field
 * @param {String|Array} val
 * @return {ServerResponse} for chaining
 * @public
 */

A deeper dive into the code shows us that this is really just a proxy for node's response.setHeader(), which follows the same format

Sets a single header value for implicit headers. If this header already exists in the to-be-sent headers, its value will be replaced. Use an array of strings here if you need to send multiple headers with the same name.

response.setHeader('Set-Cookie', ['type=ninja', 'language=javascript']);