fix: contain malformed metadata and stale discovery

well-formed-string.js

@@ -0,0 +1,42 @@
+'use strict';
+
+(function exposeWellFormedString(root, factory) {
+  const api = factory();
+  if (typeof module !== 'undefined' && module.exports) module.exports = api;
+  if (root) root.AptWellFormedString = api;
+}(typeof window !== 'undefined' ? window : undefined, function wellFormedStringFactory() {
+  function manualToWellFormed(value) {
+    let result = '';
+    for (let index = 0; index < value.length; index += 1) {
+      const codeUnit = value.charCodeAt(index);
+      if (codeUnit >= 0xd800 && codeUnit <= 0xdbff) {
+        const next = value.charCodeAt(index + 1);
+        if (next >= 0xdc00 && next <= 0xdfff) {
+          result += value[index] + value[index + 1];
+          index += 1;
+        } else {
+          result += '\ufffd';
+        }
+      } else if (codeUnit >= 0xdc00 && codeUnit <= 0xdfff) {
+        result += '\ufffd';
+      } else {
+        result += value[index];
+      }
+    }
+    return result;
+  }
+
+  function toWellFormedString(value, fallback = '') {
+    let string;
+    try {
+      string = String(value);
+    } catch {
+      string = String(fallback);
+    }
+    return typeof string.toWellFormed === 'function'
+      ? string.toWellFormed()
+      : manualToWellFormed(string);
+  }
+
+  return Object.freeze({ toWellFormedString });
+}));