Performs the low-level validations on the provided value that are done when res.setHeader(name, value) is called.

Passing illegal value as value will result in a TypeError being thrown.

• Undefined value error is identified by code: 'ERR_HTTP_INVALID_HEADER_VALUE'.
• Invalid value character error is identified by code: 'ERR_INVALID_CHAR'.

It is not necessary to use this method before passing headers to an HTTP request or response. The HTTP module will automatically validate such headers.

Examples:

import { validateHeaderValue } from 'node:http';

try {
  validateHeaderValue('x-my-header', undefined);
} catch (err) {
  console.error(err instanceof TypeError); // --> true
  console.error(err.code === 'ERR_HTTP_INVALID_HEADER_VALUE'); // --> true
  console.error(err.message); // --> 'Invalid value "undefined" for header "x-my-header"'
}

try {
  validateHeaderValue('x-my-header', 'oʊmɪɡə');
} catch (err) {
  console.error(err instanceof TypeError); // --> true
  console.error(err.code === 'ERR_INVALID_CHAR'); // --> true
  console.error(err.message); // --> 'Invalid character in header content ["x-my-header"]'
}