Use Set instead of Map in constants

rehypejs · Sep 16, 2023 · 9a0ceb8 · 9a0ceb8
1 parent 75f62e7
commit 9a0ceb8
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Showing 2 changed files with 24 additions and 33 deletions.
diff --git a/lib/constants.js b/lib/constants.js
@@ -49,45 +49,36 @@ export const securityHeaders = {
  * remote server.
  * Only those present and true are forwarded.
  *
- * @type {Readonly<Map<string, boolean>>}
+ * @type {Readonly<Set<string>>}
  */
-export const defaultRequestHeaders = new Map([
-  ['Accept', true],
-  ['Accept-Charset', true],
-  // No `Accept-Encoding` because images (other than from XML or SVG), don’t
-  // typically benefit from compression:
-  ['Accept-Encoding', false],
-  ['Accept-Language', true],
-  ['Cache-Control', true],
-  ['If-None-Match', true],
-  ['If-Modified-Since', true],
-  // `Range` is used by Safari for byte range requests on video:
-  ['Range', true],
-  // No `X-Forwarded-For` because ???
-  ['X-Forwarded-For', false]
+export const defaultRequestHeaders = new Set([
+  'Accept',
+  'Accept-Charset',
+  'Accept-Language',
+  'Cache-Control',
+  'If-None-Match',
+  'If-Modified-Since',
+  'Range' // used by Safari for byte range requests on video
 ])
 
 /**
  * HTTP response headers that are acceptable to pass from the remote server to
  * the client.
  * Only those present and true are forwarded.
  *
- * @type {Readonly<Map<string, boolean>>}
+ * @type {Readonly<Set<string>>}
  */
-export const defaultResponseHeaders = new Map([
-  // `Accept-Ranges` is used by Safari for byte range requests on video:
-  ['Accept-Ranges', true],
-  ['Cache-Control', true],
-  ['Content-Length', true],
-  ['Content-Encoding', true],
-  ['Content-Range', true],
-  ['Content-Type', true],
-  ['ETag', true],
-  ['Expires', true],
-  ['Last-Modified', true],
-  // `Server` is disallowed because ???
-  ['Server', false],
-  ['Transfer-Encoding', true]
+export const defaultResponseHeaders = new Set([
+  'Accept-Ranges', // used by Safari for byte range requests on video
+  'Cache-Control',
+  'Content-Length',
+  'Content-Encoding',
+  'Content-Range',
+  'Content-Type',
+  'ETag',
+  'Expires',
+  'Last-Modified',
+  'Transfer-Encoding'
 ])
 
 /**

diff --git a/lib/server.js b/lib/server.js
@@ -24,18 +24,18 @@ import {
  * Filter incoming headers based on allowed headers.
  * We always want to send Pascal-Case headers so we use the key from constants
  * with the value from the incoming header.
- * @param {Map<string, boolean>} allowedHeaders
+ * @param {Set<string>} allowedHeaders
  * @returns {(incomingHeaders: Headers) => Record<string, string>}
  * */
 function filterHeaders(allowedHeaders) {
   return function (incomingHeaders) {
     /** @type {Record<string, string>} */
     const filteredHeaders = {}
 
-    for (const [key, bool] of allowedHeaders.entries()) {
+    for (const key of allowedHeaders.keys()) {
       const value = incomingHeaders.get(key.toLowerCase())
 
-      if (value !== null && value !== undefined && bool) {
+      if (value !== null && value !== undefined) {
         filteredHeaders[key] = value
       }
     }