1 files changed, 13 insertions, 3 deletions

diff --git a/src/data/thing.js b/src/data/thing.js
index c51c5fe5..f719224d 100644
--- a/src/data/thing.js
+++ b/src/data/thing.js
@@ -21,6 +21,14 @@ export default class Thing extends CacheableObject {
   static yamlDocumentSpec = Symbol.for('Thing.yamlDocumentSpec');
   static getYamlLoadingSpec = Symbol.for('Thing.getYamlLoadingSpec');
 
+  static yamlSourceFilename = Symbol.for('Thing.yamlSourceFilename');
+  static yamlSourceDocument = Symbol.for('Thing.yamlSourceDocument');
+  static yamlSourceDocumentPlacement = Symbol.for('Thing.yamlSourceDocumentPlacement');
+
+  [Symbol.for('Thing.yamlSourceFilename')] = null;
+  [Symbol.for('Thing.yamlSourceDocument')] = null;
+  [Symbol.for('Thing.yamlSourceDocumentPlacement')] = null;
+
   static isThingConstructor = Symbol.for('Thing.isThingConstructor');
   static isThing = Symbol.for('Thing.isThing');
 
@@ -29,11 +37,13 @@ export default class Thing extends CacheableObject {
   static [Symbol.for('Thing.isThingConstructor')] = NaN;
 
   constructor() {
-    super();
+    super({seal: false});
 
     // To detect:
     // Object.hasOwn(object, Symbol.for('Thing.isThing'))
     this[Symbol.for('Thing.isThing')] = NaN;
+
+    Object.seal(this);
   }
 
   static [Symbol.for('Thing.selectAll')] = _wikiData => [];
@@ -50,7 +60,7 @@ export default class Thing extends CacheableObject {
       if (this.name) {
         name = colors.green(`"${this.name}"`);
       }
-    } catch (error) {
+    } catch {
       name = colors.yellow(`couldn't get name`);
     }
 
@@ -59,7 +69,7 @@ export default class Thing extends CacheableObject {
       if (this.directory) {
         reference = colors.blue(Thing.getReference(this));
       }
-    } catch (error) {
+    } catch {
       reference = colors.yellow(`couldn't get reference`);
     }