Anki template regex helper updates (#1934)

* Update regexReplace and regexMatch to support content arguments

* Update documentation

2 files changed, 24 insertions, 10 deletions

diff --git a/docs/templates.md b/docs/templates.md
index 1cc7e210..638c79a6 100644
--- a/docs/templates.md
+++ b/docs/templates.md
@@ -146,7 +146,8 @@ Uses a [regular expression](https://developer.mozilla.org/en-US/docs/Web/JavaScr
 <details>
   <summary>Syntax:</summary>
 
-  <code>{{#regexReplace <i>regex</i> <i>replacement</i> <i>[flags]</i>}}<i>text-to-modify</i>{{/regexReplace}}</code>
+  <code>{{#regexReplace <i>regex</i> <i>replacement</i> <i>[flags]</i>}}<i>text-to-modify</i>{{/regexReplace}}</code><br>
+  <code>{{#regexReplace <i>regex</i> <i>replacement</i> <i>[flags]</i> <i>[text-to-modify]...</i>}}{{/regexReplace}}</code><br>
 
   * _`regex`_ <br>
     The raw string used to create the regular expression. This value is passed to the [`RegExp`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/RegExp) constructor.
@@ -156,6 +157,7 @@ Uses a [regular expression](https://developer.mozilla.org/en-US/docs/Web/JavaScr
     Optional flags to pass to the [`RegExp`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/RegExp) constructor.
   * _`text-to-modify`_ <br>
     The text that the regular expression is applied to.
+    If multiple arguments are present, they are all concatenated.
 </details>
 <details>
   <summary>Example:</summary>
@@ -178,7 +180,8 @@ Uses a [regular expression](https://developer.mozilla.org/en-US/docs/Web/JavaScr
 <details>
   <summary>Syntax:</summary>
 
-  <code>{{#regexMatch <i>regex</i> <i>[flags]</i>}}<i>text-to-modify</i>{{/regexMatch}}</code>
+  <code>{{#regexMatch <i>regex</i> <i>[flags]</i>}}<i>text-to-modify</i>{{/regexMatch}}</code><br>
+  <code>{{#regexMatch <i>regex</i> <i>[flags]</i> <i>[text-to-modify]...</i>}}{{/regexMatch}}</code><br>
 
   * _`regex`_ <br>
     The raw string used to create the regular expression. This value is passed to the [`RegExp`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/RegExp) constructor.
@@ -186,6 +189,7 @@ Uses a [regular expression](https://developer.mozilla.org/en-US/docs/Web/JavaScr
     Optional flags to pass to the [`RegExp`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/RegExp) constructor.
   * _`text-to-modify`_ <br>
     The text that the regular expression is applied to.
+    If multiple arguments are present, they are all concatenated.
 </details>
 <details>
   <summary>Example:</summary>
diff --git a/ext/js/templates/sandbox/anki-template-renderer.js b/ext/js/templates/sandbox/anki-template-renderer.js
index 8a257bcc..fab0ed3f 100644
--- a/ext/js/templates/sandbox/anki-template-renderer.js
+++ b/ext/js/templates/sandbox/anki-template-renderer.js
@@ -206,15 +206,20 @@ class AnkiTemplateRenderer {
 
     _regexReplace(context, ...args) {
         // Usage:
-        // {{#regexReplace regex string [flags]}}content{{/regexReplace}}
+        // {{#regexReplace regex string [flags] [content]...}}content{{/regexReplace}}
         // regex: regular expression string
         // string: string to replace
         // flags: optional flags for regular expression
         //   e.g. "i" for case-insensitive, "g" for replace all
-        let value = args[args.length - 1].fn(context);
-        if (args.length >= 3) {
+        const argCount = args.length - 1;
+        const options = args[argCount];
+        let value = options.fn(context);
+        if (argCount > 3) {
+            value = `${args.slice(3).join('')}${value}`;
+        }
+        if (argCount > 1) {
             try {
-                const flags = args.length > 3 ? args[2] : 'g';
+                const flags = argCount > 2 ? args[2] : 'g';
                 const regex = new RegExp(args[0], flags);
                 value = value.replace(regex, args[1]);
             } catch (e) {
@@ -226,14 +231,19 @@ class AnkiTemplateRenderer {
 
     _regexMatch(context, ...args) {
         // Usage:
-        // {{#regexMatch regex [flags]}}content{{/regexMatch}}
+        // {{#regexMatch regex [flags] [content]...}}content{{/regexMatch}}
         // regex: regular expression string
         // flags: optional flags for regular expression
         //   e.g. "i" for case-insensitive, "g" for match all
-        let value = args[args.length - 1].fn(context);
-        if (args.length >= 2) {
+        const argCount = args.length - 1;
+        const options = args[argCount];
+        let value = options.fn(context);
+        if (argCount > 2) {
+            value = `${args.slice(2).join('')}${value}`;
+        }
+        if (argCount > 0) {
             try {
-                const flags = args.length > 2 ? args[1] : '';
+                const flags = argCount > 1 ? args[1] : '';
                 const regex = new RegExp(args[0], flags);
                 const parts = [];
                 value.replace(regex, (g0) => parts.push(g0));