* first action! (#1)

node_modules/make-fetch-happen/warning.js

@@ -0,0 +1,24 @@
+const url = require('url')
+
+module.exports = setWarning
+
+function setWarning (reqOrRes, code, message, replace) {
+  //   Warning    = "Warning" ":" 1#warning-value
+  // warning-value = warn-code SP warn-agent SP warn-text [SP warn-date]
+  // warn-code  = 3DIGIT
+  // warn-agent = ( host [ ":" port ] ) | pseudonym
+  //                 ; the name or pseudonym of the server adding
+  //                 ; the Warning header, for use in debugging
+  // warn-text  = quoted-string
+  // warn-date  = <"> HTTP-date <">
+  // (https://tools.ietf.org/html/rfc2616#section-14.46)
+  const host = url.parse(reqOrRes.url).host
+  const jsonMessage = JSON.stringify(message)
+  const jsonDate = JSON.stringify(new Date().toUTCString())
+  const header = replace ? 'set' : 'append'
+
+  reqOrRes.headers[header](
+    'Warning',
+    `${code} ${host} ${jsonMessage} ${jsonDate}`
+  )
+}