Merge pull request #10 from maxmorozoff/try-catch-tuple/dev

Refactor and Document TryCatch Types

Author: maxmorozoff

.changeset/shy-trees-lose.md

@@ -0,0 +1,20 @@
+---
+"@maxmorozoff/try-catch-tuple": patch
+---
+
+docs:
+
+- Add JSDoc for TryCatch types
+
+chore:
+
+- Export missing types
+- Update default error type
+- Update Branded type
+- Update DataErrorTuple type (e.g., `rest` is now `never[]`)
+- Restrict array methods on DataErrorTuple
+- Make `fn` parameter required
+
+refactor:
+
+- Extract DataErrorTuple to type alias

README.md

@@ -483,7 +483,7 @@ type Result<T, E = Error> = ([data: T, error: null] | [data: null, error: E]) &
 ### Edge Cases
 
 ```ts
-tryCatch(); // Returns [undefined, null]
+tryCatch(undefined); // Returns [undefined, null]
 tryCatch(null); // Returns [null, null]
 tryCatch(() => {
   throw new Error("Unexpected Error");

packages/try-catch-tuple/README.md

@@ -266,7 +266,7 @@ type Result<T, E = Error> = [data: T, error: null] | [data: null, error: E];
 ## Edge Cases
 
 ```ts
-tryCatch(); // Returns [undefined, null]
+tryCatch(undefined); // Returns [undefined, null]
 tryCatch(null); // Returns [null, null]
 tryCatch(() => {
   throw new Error("Unexpected Error");

packages/try-catch-tuple/src/tryCatch.ts

@@ -1,42 +1,104 @@
-type Branded<T> = T & { __tryCatchTupleResult: any };
-type Success<T> = Branded<[data: T, error: null]>;
-type Failure<E> = Branded<[data: null, error: E | Error]>;
-type Result<T, E> = Success<T> | Failure<E>;
+type Branded<T> = T & { __tryCatchTupleResult: never };
+type DisableArrayMethods<T> = T & {
+  [K in Exclude<keyof Array<any>, "length" | symbol>]: never;
+};
+
+type DataErrorTuple<T, E> = Branded<
+  DisableArrayMethods<[data: T, error: E] & never[]>
+>;
+
+/**
+ * Represents a successful result where `data` is present and `error` is `null`.
+ */
+export type Success<T> = DataErrorTuple<T, null>;
+
+/**
+ * Represents a failure result where `error` contains an error instance and `data` is `null`.
+ */
+export type Failure<E extends Error> = DataErrorTuple<null, E | Error>;
+
+/**
+ * Represents the result of an operation that can either succeed with `T` or fail with `E`.
+ */
+export type Result<T, E extends Error> = Success<T> | Failure<E>;
 
-type TryCatchResult<T, E> = T extends Promise<infer U>
+/**
+ * Resolves the return type based on whether `T` is a promise:
+ * - If `T` is a `Promise<U>`, returns `Promise<Result<U, E>>`.
+ * - Otherwise, returns `Result<T, E>`.
+ */
+export type TryCatchResult<T, E extends Error> = T extends Promise<infer U>
   ? Promise<Result<U, E>>
   : Result<T, E>;
 
-type TryCatchFunc<E_ extends Error = never> = <T, E extends Error = E_>(
-  fn?: T | (() => T),
+/**
+ * Function type for handling try-catch logic.
+ *
+ * @template E_ Default error type.
+ * @template T The return type of the function being executed.
+ * @template E The error type that extends the default error type.
+ *
+ * @param fn A function, promise, or value to execute within a try-catch block.
+ * @param operationName Optional name added to `error.message` for better debugging and context.
+ */
+export type TryCatchFunc<E_ extends Error = Error> = <T, E extends Error = E_>(
+  fn: T | (() => T),
   operationName?: string,
 ) => TryCatchResult<T, E>;
 
-type TryCatch<
+/**
+ * A utility for handling synchronous and asynchronous operations within a try-catch block.
+ *
+ * @template F The function type for try-catch execution.
+ * @template E_ The base error type.
+ */
+export type TryCatch<
   F extends TryCatchFunc = TryCatchFunc,
-  E_ extends Error = never,
+  E_ extends Error = Error,
 > = F & {
+  /**
+   * Executes a synchronous function inside a try-catch block.
+   *
+   * @param fn The function to execute.
+   * @param operationName Optional name added to `error.message` for better debugging and context.
+   * @returns A `Result<T, E>` indicating success or failure.
+   */
   sync: <T, E extends Error = E_>(
     fn: () => T,
     operationName?: string,
   ) => Result<T, E>;
+
+  /**
+   * Executes an asynchronous function inside a try-catch block.
+   *
+   * @param fn The function or promise to execute.
+   * @param operationName Optional name added to `error.message` for better debugging and context.
+   * @returns A `Promise<Result<T, E>>` indicating success or failure.
+   */
   async: <T, E extends Error = E_>(
     fn: Promise<T> | (() => Promise<T>),
     operationName?: string,
   ) => Promise<Result<T, E>>;
+
+  /**
+   * Creates a new `TryCatch` instance that handles additional error types.
+   *
+   * @template E Extends the existing error type.
+   * @returns A new `TryCatch` instance with extended error handling capabilities.
+   */
   errors: <E extends Error>() => TryCatch<TryCatchFunc<E | E_>, E | E_>;
 };
 
 /**
  * tryCatch - Error handling that can be synchronous or asynchronous
  * based on the input function.
  *
- * @param fn Function to execute, Promise or value.
- * @param operationName Optional name for context.
+ * @param fn A function, promise, or value to execute within a try-catch block.
+ * @param operationName Optional name added to `error.message` for better debugging and context.
  * @returns A Result, or a Promise resolving to a Result, depending on fn.
  */
-export const tryCatch: TryCatch = <T, E extends Error = never>(
-  fn?: T | (() => T),
+export const tryCatch: TryCatch = <T, E extends Error = Error>(
+  fn: T | (() => T),
   operationName?: string,
 ) => {
   try {
@@ -51,7 +113,7 @@ export const tryCatch: TryCatch = <T, E extends Error = never>(
   }
 };
 
-export const tryCatchSync: TryCatch["sync"] = <T, E extends Error = never>(
+export const tryCatchSync: TryCatch["sync"] = <T, E extends Error = Error>(
   fn: () => T,
   operationName?: string,
 ) => {
@@ -65,7 +127,7 @@ export const tryCatchSync: TryCatch["sync"] = <T, E extends Error = never>(
 
 export const tryCatchAsync: TryCatch["async"] = async <
   T,
-  E extends Error = never,
+  E extends Error = Error,
 >(
   fn: Promise<T> | (() => Promise<T>),
   operationName?: string,

packages/try-catch-tuple/tests/tryCatch.test.ts

@@ -344,7 +344,8 @@ describe("tryCatch", () => {
 
   describe("edge cases", () => {
     test("should handle undefined fn", () => {
-      const [result, error] = tryCatch();
+      const [result, error] = tryCatch(undefined);
+      if (error) expect.unreachable();
       expect(result).toBe(undefined);
       expect(error).toBeNil();
     });