index.js
function createHeaderGetter(str) {
  var header = str.toLowerCase()

  return headerGetter

  function headerGetter(req, res) {
    // set appropriate Vary header
    res.vary(str)

    // multiple headers get joined with comma by node.js core
    return (req.headers[header] || '').split(/ *, */)
  }
}
function createHeaderGetter(str) {
  var header = str.toLowerCase()

  return headerGetter

  function headerGetter(req, res) {
    // set appropriate Vary header
    res.vary(str)

    // multiple headers get joined with comma by node.js core
    return (req.headers[header] || '').split(/ *, */)
  }
}
function createHeaderGetter ( str ) { var header = str . toLowerCase ( ) return headerGetter function headerGetter ( req , res ) { // set appropriate Vary header res . vary ( str ) // multiple headers get joined with comma by node.js core return ( req . headers [ header ] || '' ) . split ( /  *, * / ) } }
Create a getter for the given header name.
Create a getter for the given header name .