fix: CJK content results in long context strings in search results

closes #7183

shared/utils/string.ts

@@ -0,0 +1,65 @@
+/**
+ * Returns the index of the first occurrence of a substring in a string that matches a regular expression.
+ *
+ * @param text The string to search in.
+ * @param re The regular expression to search for.
+ * @param startPos The position in the string at which to begin the search. Defaults to 0.
+ */
+export const regexIndexOf = function (
+  text: string,
+  re: RegExp,
+  startPos?: number
+) {
+  startPos = startPos || 0;
+
+  if (!re.global) {
+    const flags = "g" + (re.multiline ? "m" : "") + (re.ignoreCase ? "i" : "");
+    re = new RegExp(re.source, flags);
+  }
+
+  re.lastIndex = startPos;
+  const match = re.exec(text);
+
+  if (match) {
+    return match.index;
+  } else {
+    return -1;
+  }
+};
+
+/**
+ * Returns the index of the last occurrence of a substring in a string that matches a regular expression.
+ *
+ * @param text The string to search in.
+ * @param re The regular expression to search for.
+ * @param startPos The position in the string at which to begin the search. Defaults to the end of the string.
+ */
+export const regexLastIndexOf = function (
+  text: string,
+  re: RegExp,
+  startPos?: number
+) {
+  startPos = startPos === undefined ? text.length : startPos;
+
+  if (!re.global) {
+    const flags = "g" + (re.multiline ? "m" : "") + (re.ignoreCase ? "i" : "");
+    re = new RegExp(re.source, flags);
+  }
+
+  let lastSuccess = -1;
+  for (let pos = 0; pos <= startPos; pos++) {
+    re.lastIndex = pos;
+
+    const match = re.exec(text);
+    if (!match) {
+      break;
+    }
+
+    pos = match.index;
+    if (pos <= startPos) {
+      lastSuccess = pos;
+    }
+  }
+
+  return lastSuccess;
+};