refactor: updater errors

src/commands/changeStatus.test.ts

@@ -1,7 +1,7 @@
 import { beforeEach, describe, expect, it } from "vitest";
 import { err } from "neverthrow";
 import { InMemoryFileSystem } from "../../tests/helpers/InMemoryFileSystem";
-import { AppError } from "@/error";
+import { appError, AppErrorVariant } from "@/error";
 import { FsTaskRepository } from "@/storage/FsTaskRepository";
 import { changeStatus } from "./changeStatus";
 
@@ -38,13 +38,15 @@ describe("changeStatus", () => {
 		expect(stored?.status).toBe("in-progress");
 	});
 
-	it("returns not_found for unknown id", async () => {
+	it("returns not-found for unknown id", async () => {
 		const result = await changeStatus(repo, {
 			folderPath: folder,
 			id: "missing",
 			status: "done",
 		});
-		expect(result).toEqual(err(AppError.notFound()));
+		expect(result).toEqual(
+			err(appError(AppErrorVariant.NOT_FOUND, { id: "missing" })),
+		);
 	});
 
 	it("rejects missing folder", async () => {
@@ -53,7 +55,7 @@ describe("changeStatus", () => {
 			id: "x",
 			status: "done",
 		});
-		expect(result).toEqual(err(AppError.noFolder()));
+		expect(result).toEqual(err(appError(AppErrorVariant.NO_FOLDER)));
 	});
 
 	it("rejects missing id", async () => {
@@ -62,7 +64,7 @@ describe("changeStatus", () => {
 			id: undefined,
 			status: "done",
 		});
-		expect(result).toEqual(err(AppError.noId()));
+		expect(result).toEqual(err(appError(AppErrorVariant.NO_ID)));
 	});
 
 	it("rejects missing status", async () => {
@@ -71,6 +73,6 @@ describe("changeStatus", () => {
 			id: "x",
 			status: undefined,
 		});
-		expect(result).toEqual(err(AppError.noStatus()));
+		expect(result).toEqual(err(appError(AppErrorVariant.NO_STATUS)));
 	});
 });

src/commands/changeStatus.ts

@@ -1,5 +1,5 @@
 import { errAsync, okAsync, ResultAsync } from "neverthrow";
-import { AppError } from "@/error";
+import { appError, AppError, AppErrorVariant } from "@/error";
 import { Task, TaskStatus } from "@/model/task";
 import { ITaskRepository } from "@/ports";
 
@@ -14,13 +14,13 @@ export function changeStatus(
 	input: ChangeStatusInput,
 ): ResultAsync<Task, AppError> {
 	if (input.folderPath === undefined) {
-		return errAsync(AppError.noFolder());
+		return errAsync(appError(AppErrorVariant.NO_FOLDER));
 	}
 	if (input.id === undefined) {
-		return errAsync(AppError.noId());
+		return errAsync(appError(AppErrorVariant.NO_ID));
 	}
 	if (input.status === undefined) {
-		return errAsync(AppError.noStatus());
+		return errAsync(appError(AppErrorVariant.NO_STATUS));
 	}
 
 	const folderPath = input.folderPath;
@@ -30,7 +30,7 @@ export function changeStatus(
 	return ResultAsync.fromSafePromise(repo.getById(folderPath, id)).andThen(
 		(existing) => {
 			if (!existing) {
-				return errAsync(AppError.notFound());
+				return errAsync(appError(AppErrorVariant.NOT_FOUND, { id }));
 			}
 
 			const next: Task = { ...existing, status };
@@ -38,7 +38,9 @@ export function changeStatus(
 				() =>
 					ResultAsync.fromSafePromise(repo.getById(folderPath, id)).andThen(
 						(updated) =>
-							updated ? okAsync(updated) : errAsync(AppError.notFound()),
+							updated
+								? okAsync(updated)
+								: errAsync(appError(AppErrorVariant.NOT_FOUND, { id })),
 					),
 			);
 		},

src/commands/createTask.test.ts

@@ -1,7 +1,7 @@
 import { beforeEach, describe, expect, it } from "vitest";
 import { err } from "neverthrow";
 import { InMemoryFileSystem } from "../../tests/helpers/InMemoryFileSystem";
-import { AppError } from "@/error";
+import { appError, AppErrorVariant } from "@/error";
 import { FsTaskRepository } from "@/storage/FsTaskRepository";
 import { createTask } from "./createTask";
 
@@ -39,7 +39,7 @@ describe("createTask", () => {
 			folderPath: folder,
 			title: "   ",
 		});
-		expect(result).toEqual(err(AppError.emptyTitle()));
+		expect(result).toEqual(err(appError(AppErrorVariant.EMPTY_TITLE)));
 		expect(await repo.list(folder)).toEqual([]);
 	});
 
@@ -48,7 +48,7 @@ describe("createTask", () => {
 			folderPath: folder,
 			title: undefined,
 		});
-		expect(result).toEqual(err(AppError.emptyTitle()));
+		expect(result).toEqual(err(appError(AppErrorVariant.EMPTY_TITLE)));
 	});
 
 	it("rejects missing folder", async () => {
@@ -56,6 +56,6 @@ describe("createTask", () => {
 			folderPath: undefined,
 			title: "Task",
 		});
-		expect(result).toEqual(err(AppError.noFolder()));
+		expect(result).toEqual(err(appError(AppErrorVariant.NO_FOLDER)));
 	});
 });

src/commands/createTask.ts

@@ -1,5 +1,5 @@
 import { errAsync, ResultAsync } from "neverthrow";
-import { AppError } from "@/error";
+import { appError, AppError, AppErrorVariant } from "@/error";
 import { Task } from "@/model/task";
 import { ITaskRepository } from "@/ports";
 
@@ -13,12 +13,12 @@ export function createTask(
 	input: CreateTaskInput,
 ): ResultAsync<Task, AppError> {
 	if (input.folderPath === undefined) {
-		return errAsync(AppError.noFolder());
+		return errAsync(appError(AppErrorVariant.NO_FOLDER));
 	}
 
 	const title = input.title?.trim() ?? "";
 	if (!title) {
-		return errAsync(AppError.emptyTitle());
+		return errAsync(appError(AppErrorVariant.EMPTY_TITLE));
 	}
 
 	return ResultAsync.fromSafePromise(

src/commands/deleteTask.test.ts

@@ -1,7 +1,7 @@
 import { beforeEach, describe, expect, it } from "vitest";
 import { err, ok } from "neverthrow";
 import { InMemoryFileSystem } from "../../tests/helpers/InMemoryFileSystem";
-import { AppError } from "@/error";
+import { appError, AppErrorVariant } from "@/error";
 import { FsTaskRepository } from "@/storage/FsTaskRepository";
 import { deleteTask } from "./deleteTask";
 
@@ -32,12 +32,14 @@ describe("deleteTask", () => {
 		expect(await repo.list(folder)).toEqual([]);
 	});
 
-	it("returns not_found for unknown id", async () => {
+	it("returns not-found for unknown id", async () => {
 		const result = await deleteTask(repo, {
 			folderPath: folder,
 			id: "missing",
 		});
-		expect(result).toEqual(err(AppError.notFound()));
+		expect(result).toEqual(
+			err(appError(AppErrorVariant.NOT_FOUND, { id: "missing" })),
+		);
 	});
 
 	it("rejects missing folder", async () => {
@@ -45,7 +47,7 @@ describe("deleteTask", () => {
 			folderPath: undefined,
 			id: "x",
 		});
-		expect(result).toEqual(err(AppError.noFolder()));
+		expect(result).toEqual(err(appError(AppErrorVariant.NO_FOLDER)));
 	});
 
 	it("rejects missing id", async () => {
@@ -53,6 +55,6 @@ describe("deleteTask", () => {
 			folderPath: folder,
 			id: undefined,
 		});
-		expect(result).toEqual(err(AppError.noId()));
+		expect(result).toEqual(err(appError(AppErrorVariant.NO_ID)));
 	});
 });

src/commands/deleteTask.ts

@@ -1,5 +1,5 @@
 import { errAsync, ResultAsync } from "neverthrow";
-import { AppError } from "@/error";
+import { appError, AppError, AppErrorVariant } from "@/error";
 import { ITaskRepository } from "@/ports";
 
 export type DeleteTaskInput = {
@@ -12,10 +12,10 @@ export function deleteTask(
 	input: DeleteTaskInput,
 ): ResultAsync<void, AppError> {
 	if (input.folderPath === undefined) {
-		return errAsync(AppError.noFolder());
+		return errAsync(appError(AppErrorVariant.NO_FOLDER));
 	}
 	if (input.id === undefined) {
-		return errAsync(AppError.noId());
+		return errAsync(appError(AppErrorVariant.NO_ID));
 	}
 
 	const folderPath = input.folderPath;
@@ -24,7 +24,7 @@ export function deleteTask(
 	return ResultAsync.fromSafePromise(repo.getById(folderPath, id)).andThen(
 		(existing) => {
 			if (!existing) {
-				return errAsync(AppError.notFound());
+				return errAsync(appError(AppErrorVariant.NOT_FOUND, { id }));
 			}
 			return ResultAsync.fromSafePromise(repo.delete(folderPath, id));
 		},

src/commands/openTask.test.ts

@@ -1,7 +1,7 @@
 import { beforeEach, describe, expect, it } from "vitest";
 import { err } from "neverthrow";
 import { InMemoryFileSystem } from "../../tests/helpers/InMemoryFileSystem";
-import { AppError } from "@/error";
+import { appError, AppErrorVariant } from "@/error";
 import { FsTaskRepository } from "@/storage/FsTaskRepository";
 import { openTask } from "./openTask";
 
@@ -34,12 +34,14 @@ describe("openTask", () => {
 		expect(result.value.task).toEqual(created);
 	});
 
-	it("returns not_found for unknown id", async () => {
+	it("returns not-found for unknown id", async () => {
 		const result = await openTask(repo, {
 			folderPath: folder,
 			id: "missing",
 		});
-		expect(result).toEqual(err(AppError.notFound()));
+		expect(result).toEqual(
+			err(appError(AppErrorVariant.NOT_FOUND, { id: "missing" })),
+		);
 	});
 
 	it("rejects missing folder", async () => {
@@ -47,7 +49,7 @@ describe("openTask", () => {
 			folderPath: undefined,
 			id: "x",
 		});
-		expect(result).toEqual(err(AppError.noFolder()));
+		expect(result).toEqual(err(appError(AppErrorVariant.NO_FOLDER)));
 	});
 
 	it("rejects missing id", async () => {
@@ -55,6 +57,6 @@ describe("openTask", () => {
 			folderPath: folder,
 			id: undefined,
 		});
-		expect(result).toEqual(err(AppError.noId()));
+		expect(result).toEqual(err(appError(AppErrorVariant.NO_ID)));
 	});
 });

src/commands/openTask.ts

@@ -1,5 +1,5 @@
 import { errAsync, okAsync, ResultAsync } from "neverthrow";
-import { AppError } from "@/error";
+import { appError, AppError, AppErrorVariant } from "@/error";
 import { Task } from "@/model/task";
 import { ITaskRepository } from "@/ports";
 
@@ -18,10 +18,10 @@ export function openTask(
 	input: OpenTaskInput,
 ): ResultAsync<OpenTaskValue, AppError> {
 	if (input.folderPath === undefined) {
-		return errAsync(AppError.noFolder());
+		return errAsync(appError(AppErrorVariant.NO_FOLDER));
 	}
 	if (input.id === undefined) {
-		return errAsync(AppError.noId());
+		return errAsync(appError(AppErrorVariant.NO_ID));
 	}
 
 	const folderPath = input.folderPath;
@@ -30,7 +30,7 @@ export function openTask(
 	return ResultAsync.fromSafePromise(repo.getById(folderPath, id)).andThen(
 		(task) => {
 			if (!task) {
-				return errAsync(AppError.notFound());
+				return errAsync(appError(AppErrorVariant.NOT_FOUND, { id }));
 			}
 			return okAsync({
 				path: repo.getFilePath(folderPath, task),

src/error.test.ts

@@ -0,0 +1,36 @@
+import { describe, expect, it } from "vitest";
+import { appError, AppErrorVariant, formatMessage } from "./error";
+
+describe("formatMessage", () => {
+	it("substitutes placeholders", () => {
+		expect(formatMessage("Task not found: {id}", { id: "abc" })).toBe(
+			"Task not found: abc",
+		);
+	});
+
+	it("drops empty placeholders and cleans spacing", () => {
+		expect(formatMessage("Task not found: {id}", {})).toBe("Task not found:");
+		expect(formatMessage("Invalid message{detail}", {})).toBe(
+			"Invalid message",
+		);
+		expect(
+			formatMessage("Invalid message{detail}", { detail: ": explode" }),
+		).toBe("Invalid message: explode");
+	});
+});
+
+describe("appError", () => {
+	it("builds variant + message", () => {
+		expect(appError(AppErrorVariant.NOT_FOUND, { id: "x" })).toEqual({
+			variant: AppErrorVariant.NOT_FOUND,
+			message: "Task not found: x",
+		});
+	});
+
+	it("works without params", () => {
+		expect(appError(AppErrorVariant.NO_FOLDER)).toEqual({
+			variant: AppErrorVariant.NO_FOLDER,
+			message: "Task folder is not set",
+		});
+	});
+});

src/error.ts

@@ -1,20 +1,57 @@
-/** All application-level error codes. */
-export type AppErrorCode =
-	| "no_folder"
-	| "no_id"
-	| "no_status"
-	| "empty_title"
-	| "not_found";
+export const AppErrorVariant = {
+	NO_FOLDER: "no-folder",
+	NO_ID: "no-id",
+	NO_STATUS: "no-status",
+	NO_DESCRIPTION: "no-description",
+	EMPTY_TITLE: "empty-title",
+	NOT_FOUND: "not-found",
+	INVALID_MESSAGE: "invalid-message",
+} as const;
+
+export type AppErrorVariant =
+	(typeof AppErrorVariant)[keyof typeof AppErrorVariant];
 
-/** Discriminated app error returned via neverthrow `Result` / `ResultAsync`. */
 export type AppError = {
-	readonly code: AppErrorCode;
+	readonly variant: AppErrorVariant;
+	readonly message: string;
 };
 
-export const AppError = {
-	noFolder: (): AppError => ({ code: "no_folder" }),
-	noId: (): AppError => ({ code: "no_id" }),
-	noStatus: (): AppError => ({ code: "no_status" }),
-	emptyTitle: (): AppError => ({ code: "empty_title" }),
-	notFound: (): AppError => ({ code: "not_found" }),
-} as const;
+export type AppErrorParams = Record<string, string | number | undefined>;
+
+/** Message templates. Placeholders: `{name}` — replaced via `appError(variant, params)`. */
+const APP_ERROR_MESSAGES: Record<AppErrorVariant, string> = {
+	[AppErrorVariant.NO_FOLDER]: "Task folder is not set",
+	[AppErrorVariant.NO_ID]: "Task id is required",
+	[AppErrorVariant.NO_STATUS]: "Task status is required",
+	[AppErrorVariant.NO_DESCRIPTION]: "Task description is required",
+	[AppErrorVariant.EMPTY_TITLE]: "Task title is empty",
+	[AppErrorVariant.NOT_FOUND]: "Task not found: {id}",
+	[AppErrorVariant.INVALID_MESSAGE]: "Invalid message: {detail}",
+};
+
+export function formatMessage(
+	template: string,
+	params: AppErrorParams = {},
+): string {
+	return template
+		.replace(/\{(\w+)\}/g, (_, key: string) => {
+			const value = params[key];
+			if (value === undefined || value === "") {
+				return "";
+			}
+			return String(value);
+		})
+		.replace(/[ \t]+/g, " ")
+		.replace(/\s+([:,;.])/g, "$1")
+		.trim();
+}
+
+export function appError(
+	variant: AppErrorVariant,
+	params?: AppErrorParams,
+): AppError {
+	return {
+		variant,
+		message: formatMessage(APP_ERROR_MESSAGES[variant], params),
+	};
+}