Invalid request header "host" for IPv6 URLs

[donmccurdy]

Steps to reproduce:

npm i -g echo-body
echo-body --port 5000

const XMLHttpRequest = require('xmlhttprequest').XMLHttpRequest;
const xhr = new XMLHttpRequest();
xhr.open('GET', 'http://[2620:0:1000:4012:519:9fce:64b4:f20b]:5000', true);
xhr.send(null);

Where the address should be IPv6 local IP. Result on "server":

This is invalid per notation described here; the hostname should be enclosed by brackets:

[2620:0:1000:4012:519:9fce:64b4:f20b]:5000