small rewrite

Author: neverRare

src/compound.ts

@@ -6,8 +6,9 @@ export class ResultError extends Error {
   isHtml: boolean;
   override name = "ArrayResultError";
   constructor(message: string, options: Partial<ResultErrorOptions> = {}) {
-    super(message, { cause: options.cause });
-    this.isHtml = options.isHtml ?? false;
+    const { cause, isHtml = false } = options;
+    super(message, { cause });
+    this.isHtml = isHtml;
   }
 }
 export class TodoError extends ResultError {

src/parser/parser_lib.ts

@@ -87,11 +87,9 @@ export class Parser<T> {
 }
 export type Position = Readonly<{ position: number; length: number }>;
 export class PositionedError extends ResultError {
-  public position: null | Position;
   override name = "PositionedError";
-  constructor(message: string, position?: Position) {
+  constructor(message: string, public readonly position: null | Position = null) {
     super(message);
-    this.position = position ?? null;
   }
 }
 function withPositionedError<T>(fn: () => T, position: Position) {