Use http-errors for res.format error

History.md

@@ -8,6 +8,7 @@ unreleased
   * Ignore `Object.prototype` values in settings through `app.set`/`app.get`
   * Invoke `default` with same arguments as types in `res.format`
   * Support proper 205 responses using `res.send`
+  * Use `http-errors` for `res.format` error
   * deps: depd@2.0.0
     - Replace internal `eval` usage with `Function` constructor
     - Use instance methods on `process` to check for listeners

lib/response.js

@@ -14,6 +14,7 @@
 
 var Buffer = require('safe-buffer').Buffer
 var contentDisposition = require('content-disposition');
+var createError = require('http-errors')
 var deprecate = require('depd')('express');
 var encodeUrl = require('encodeurl');
 var escapeHtml = require('escape-html');
@@ -699,10 +700,9 @@ res.format = function(obj){
   } else if (obj.default) {
     obj.default(req, this, next)
   } else {
-    var err = new Error('Not Acceptable');
-    err.status = err.statusCode = 406;
-    err.types = normalizeTypes(keys).map(function(o){ return o.value });
-    next(err);
+    next(createError(406, {
+      types: normalizeTypes(keys).map(function (o) { return o.value })
+    }))
   }
 
   return this;

package.json

@@ -42,6 +42,7 @@
     "etag": "~1.8.1",
     "finalhandler": "1.2.0",
     "fresh": "0.5.2",
+    "http-errors": "2.0.0",
     "merge-descriptors": "1.0.1",
     "methods": "~1.1.2",
     "on-finished": "~2.3.0",