Difference between res.setHeader and res.header in node.js

 javascript - How can I set response header on express.js assets - Stack Overflow

res.setHeader() is a native method of Node.js and res.header() is an alias of res.set() method from Express framework.

Documentation: res.setHeader(), res.set()

This two methods do exactly the same thing, set the headers HTTP response. The only difference is res.setHeader() allows you only to set a singular header and res.header() will allow you to set multiple headers. So use the one fit with your needs.

res.set(field [, value])

Sets the response’s HTTP header field to value. To set multiple fields at once, pass an object as the parameter.

res.set('Content-Type', 'text/plain')

res.set({
  'Content-Type': 'text/plain',
  'Content-Length': '123',
  ETag: '12345'
})

Aliased as res.header(field [, value]).