Merge pull request #2185 from cardstack/fix-marked-encoding-bug

use pure js hash function for marked code block generation

Author: habdelra

packages/runtime-common/marked-sync.ts

@@ -1,6 +1,6 @@
 import { marked } from 'marked';
 import { sanitizeHtml } from './dompurify-runtime';
-import { md5 } from 'super-fast-md5';
+import { simpleHash } from '.';
 
 const CODEBLOCK_KEY_PREFIX = 'codeblock_';
 
@@ -12,7 +12,7 @@ export function markedSync(markdown: string) {
         // markdown, please use the `CodeBlock` modifier to render the
         // markdown.
         code(code, language = '') {
-          let id = `${CODEBLOCK_KEY_PREFIX}${md5(Date.now() + language + code)}`;
+          let id = `${CODEBLOCK_KEY_PREFIX}${simpleHash(Date.now() + language + code)}`;
           // we pass the code thru using localstorage instead of in the DOM,
           // that way we don't have to worry about escaping code. note that the
           // DOM wants to render "<template>" strings when we put them in the

packages/runtime-common/utils.ts

@@ -61,3 +61,14 @@ export function decodeWebSafeBase64(encoded: string): string {
 
   return Buffer.from(base64, 'base64').toString('utf-8');
 }
+
+// This is the djb2_xor hash function from http://www.cse.yorku.ca/~oz/hash.html
+export function simpleHash(str: string) {
+  let len = str.length;
+  let h = 5381;
+
+  for (let i = 0; i < len; i++) {
+    h = (h * 33) ^ str.charCodeAt(i);
+  }
+  return (h >>> 0).toString(16);
+}