refactor(core): remove MetaField and simplify error metadata handling

Author: tarnishablec

packages/core/__tests__/caller-trace.test.ts

@@ -1,6 +1,6 @@
 // noinspection ES6UnusedImports
 import { describe, expect, test } from "bun:test";
-import { metaOf, That } from '@thaterror/core';
+import { That } from '@thaterror/core';
 import { ResultAsync } from 'neverthrow';
 
 describe("ThatError Location Anchoring", () => {
@@ -89,7 +89,7 @@ describe("ThatError Location Anchoring", () => {
                  * 💡 THE ANCHOR POINT
                  * We call .at() here to explicitly mark this line as the "Crime Scene".
                  */
-                return AppError.SYNC_ERR().with(void 0, {stage: 'init'}).with(void 0, {region: "CN"});
+                return AppError.SYNC_ERR().with(void 0);
             }
 
             const err = businessFunction();
@@ -100,8 +100,6 @@ describe("ThatError Location Anchoring", () => {
             expect(topFrame).toContain("businessFunction");
             expect(topFrame).toContain(currentFileName);
 
-            expect(metaOf(err)).toEqual({stage: 'init', region: "CN"});
-
             // 🛡️ Noise Removal: The factory internals (define.ts) must be sliced off.
             expect(topFrame).not.toContain("define.ts");
 

packages/core/src/define.ts

@@ -10,7 +10,6 @@ import {
     type ErrorSpec,
     type ErrorUnionOfMap,
     type ExtractPayload,
-    MetaField,
     PayloadField,
     ScopeField
 } from "./types";
@@ -33,7 +32,6 @@ export function That<const M extends ErrorMap>(
             readonly [ScopeField]: symbol;
             readonly [PayloadField]: Payload;
             readonly [CodeField]: Code;
-            [MetaField]: Record<string, unknown>;
 
             constructor(
                 _caller: (...args: Payload) => ErrorUnionOfMap<M>,
@@ -47,15 +45,13 @@ export function That<const M extends ErrorMap>(
                 this[CodeField] = code;
                 this[ScopeField] = scope;
                 this[PayloadField] = args;
-                this[MetaField] = {};
 
                 Error.captureStackTrace(this, _caller);
             }
 
-            with<Mt extends Record<string, unknown>>(options?: ErrorOptions, meta?: Mt) {
+            with(options?: ErrorOptions) {
                 this.cause = options?.cause;
-                this[MetaField] = {...this[MetaField], ...meta};
-                return this as DefinedError<Code, Payload, Mt>;
+                return this;
             }
 
             is<K extends string, S extends ErrorSpec>(errorCase: ErrorCase<K, S>): this is DefinedError<K, ExtractPayload<S>> {

packages/core/src/of.ts

@@ -3,7 +3,6 @@ import {
     type DefinedError,
     type ErrorCase,
     type ErrorFamily,
-    MetaField,
     PayloadField,
     ScopeField
 } from "./types";
@@ -31,7 +30,3 @@ export function payloadOf<E extends DefinedError>(error: E): E[typeof PayloadFie
 export function codeOf<E extends DefinedError>(error: E): E[typeof CodeField] {
     return error[CodeField];
 }
-
-export function metaOf<E extends DefinedError>(error: E): Record<string, unknown> {
-    return error[MetaField] ?? {};
-}

packages/core/src/types.ts

@@ -2,20 +2,17 @@ export const ErrorBrand: unique symbol = Symbol("FErrorBrand");
 export const ScopeField: unique symbol = Symbol("FErrorScope");
 export const PayloadField: unique symbol = Symbol("FErrorPayload");
 export const CodeField: unique symbol = Symbol("FErrorCode");
-export const MetaField: unique symbol = Symbol("FErrorMeta");
 
 export interface DefinedError<
     Code extends string = string,
     Payload extends readonly unknown[] = readonly unknown[],
-    Meta = Record<string, unknown>
 > extends Error {
     readonly [ErrorBrand]: true;
     readonly [ScopeField]: symbol;
     readonly [PayloadField]: Payload;
     readonly [CodeField]: Code;
-    [MetaField]: Meta;
 
-    with<Me extends Record<string, unknown>>(options?: ErrorOptions, meta?: Me): DefinedError<Code, Payload, Meta & Me>;
+    with(options?: ErrorOptions): this;
 
     is<K extends string, S extends ErrorSpec>(errorCase: ErrorCase<K, S>): this is DefinedError<K, ExtractPayload<S>>;
 }