From efdf2c8fe374aca22863201f67fe35ae7e2a4456 Mon Sep 17 00:00:00 2001
From: Steve Howell <showell@zulip.com>
Date: Tue, 29 Mar 2022 15:14:44 +0000
Subject: [PATCH] linkifiers: Avoid parallel data structure.

We can pretty easily work with a map in the
two places that we ever relied on an array.
---
 static/js/linkifiers.js | 12 +++++-------
 static/js/markdown.js   | 19 +++++++++----------
 2 files changed, 14 insertions(+), 17 deletions(-)

diff --git a/static/js/linkifiers.js b/static/js/linkifiers.js
index ccec5601ea..2c42313038 100644
--- a/static/js/linkifiers.js
+++ b/static/js/linkifiers.js
@@ -2,8 +2,11 @@ import marked from "../third/marked/lib/marked";
 
 import * as blueslip from "./blueslip";
 
-const linkifier_map = new Map();
-export let linkifier_list = [];
+const linkifier_map = new Map(); // regex -> url
+
+export function get_linkifier_map() {
+    return linkifier_map;
+}
 
 function handleLinkifier(pattern, matches) {
     let url = linkifier_map.get(pattern);
@@ -80,7 +83,6 @@ function python_to_js_linkifier(pattern, url) {
 export function update_linkifier_rules(linkifiers) {
     // Update the marked parser with our particular set of linkifiers
     linkifier_map.clear();
-    linkifier_list = [];
 
     const marked_rules = [];
 
@@ -92,10 +94,6 @@ export function update_linkifier_rules(linkifiers) {
         }
 
         linkifier_map.set(regex, final_url);
-        linkifier_list.push({
-            pattern: regex,
-            url_format: final_url,
-        });
         marked_rules.push(regex);
     }
 
diff --git a/static/js/markdown.js b/static/js/markdown.js
index 51109290b0..961fc48512 100644
--- a/static/js/markdown.js
+++ b/static/js/markdown.js
@@ -85,13 +85,15 @@ function contains_problematic_linkifier(content) {
     // If a linkifier doesn't start with some specified characters
     // then don't render it locally. It is workaround for the fact that
     // javascript regex doesn't support lookbehind.
-    const linkifier_list = linkifiers.linkifier_list;
-    const false_linkifier_match = linkifier_list.find((re) => {
-        const pattern = /[^\s"'(,:<]/.source + re.pattern.source + /(?!\w)/.source;
+    for (const re of linkifiers.get_linkifier_map().keys()) {
+        const pattern = /[^\s"'(,:<]/.source + re.source + /(?!\w)/.source;
         const regex = new RegExp(pattern);
-        return regex.test(content);
-    });
-    return false_linkifier_match !== undefined;
+        if (regex.test(content)) {
+            return true;
+        }
+    }
+
+    return false;
 }
 
 export function contains_backend_only_syntax(content) {
@@ -286,11 +288,8 @@ export function add_topic_links(message) {
     }
     const topic = message.topic;
     const links = [];
-    const linkifier_list = linkifiers.linkifier_list;
 
-    for (const linkifier of linkifier_list) {
-        const pattern = linkifier.pattern;
-        const url = linkifier.url_format;
+    for (const [pattern, url] of linkifiers.get_linkifier_map().entries()) {
         let match;
         while ((match = pattern.exec(topic)) !== null) {
             let link_url = url;