refactor(yaml): remove anchor undefined check (#6915)

Author: timreichen

yaml/_loader_state.ts

@@ -365,9 +365,7 @@ export class LoaderState {
     const anchor = this.anchor;
     const result: unknown[] = [];
 
-    if (this.anchor !== null && typeof this.anchor !== "undefined") {
-      this.anchorMap.set(this.anchor, result);
-    }
+    if (this.anchor !== null) this.anchorMap.set(this.anchor, result);
 
     let ch = this.peek();
 
@@ -844,9 +842,7 @@ export class LoaderState {
       return false;
     }
 
-    if (this.anchor !== null && typeof this.anchor !== "undefined") {
-      this.anchorMap.set(this.anchor, result);
-    }
+    if (this.anchor !== null) this.anchorMap.set(this.anchor, result);
 
     ch = this.next();
 
@@ -1122,9 +1118,7 @@ export class LoaderState {
     let atExplicitKey = false;
     let detected = false;
 
-    if (this.anchor !== null && typeof this.anchor !== "undefined") {
-      this.anchorMap.set(this.anchor, result);
-    }
+    if (this.anchor !== null) this.anchorMap.set(this.anchor, result);
 
     let ch = this.peek();
 
@@ -1502,9 +1496,7 @@ export class LoaderState {
     }
 
     this.result = type.construct(this.result);
-    if (this.anchor !== null) {
-      this.anchorMap.set(this.anchor, this.result);
-    }
+    if (this.anchor !== null) this.anchorMap.set(this.anchor, this.result);
   }
   composeNode(
     { parentIndent, nodeContext, allowToSeek, allowCompact }: {