From 8b1afc7e3a7cd80b057afdec9eefb0726eade86f Mon Sep 17 00:00:00 2001
From: Damien Elmes <gpg@ankiweb.net>
Date: Thu, 19 May 2022 12:47:49 +1000
Subject: [PATCH] Reveal cloze answers in MathJax preview

Closes #1862
---
 ts/editable/mathjax.ts | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/ts/editable/mathjax.ts b/ts/editable/mathjax.ts
index 00a6027d8..6ef29cb57 100644
--- a/ts/editable/mathjax.ts
+++ b/ts/editable/mathjax.ts
@@ -36,6 +36,7 @@ export function convertMathjax(
     nightMode: boolean,
     fontSize: number,
 ): [string, string] {
+    input = revealClozeAnswers(input);
     const style = getStyle(getCSS(nightMode, fontSize));
 
     if (input.trim().length === 0) {
@@ -78,3 +79,9 @@ export function escapeSomeEntities(value: string): string {
 export function unescapeSomeEntities(value: string): string {
     return value.replace(/&lt;/g, "<").replace(/&gt;/g, ">").replace(/&amp;/g, "&");
 }
+
+function revealClozeAnswers(input: string): string {
+    // one-line version of regex in cloze.rs
+    const regex = /\{\{c(\d+)::(.*?)(?:::(.*?))?\}\}/gis;
+    return input.replace(regex, "[$2]");
+}