Merge pull request #3 from jsr-core/add-attempt

feat(attempt): add attempt function

Author: lambdalisue

README.md

@@ -6,6 +6,26 @@
 
 A utility pack for handling error.
 
+## attempt
+
+`attempt` is a function that executes a function and returns the result
+(`[error: unknown, value: T]`). If the function is successful, it returns
+`[undefined, value]`. If the function throws an error, it returns
+`[error, undefined]`.
+
+```ts
+import { assertEquals } from "@std/assert";
+import { attempt } from "@core/errorutil/attempt";
+
+assertEquals(attempt(() => 42), [undefined, 42]);
+assertEquals(
+  attempt(() => {
+    throw "err";
+  }),
+  ["err", undefined],
+);
+```
+
 ## ErrorObject
 
 `ErrorObject` is a class that wraps an error object for serialization. It is

attempt.ts

@@ -0,0 +1,25 @@
+export type Success<T> = [error: undefined, value: T];
+export type Failure<E> = [error: E, value: undefined];
+export type Result<T, E> = Success<T> | Failure<E>;
+
+/**
+ * Attempt to execute a function and return a Result<T, E>.
+ *
+ * @param fn - The function to execute.
+ * @returns A Result<T, E> where T is the return type of the function and E is the error type.
+ *
+ * @example
+ * ```ts
+ * import { attempt } from "@core/errorutil/attempt";
+ *
+ * console.log(attempt(() => 1)); // [undefined, 1]
+ * console.log(attempt(() => { throw "err" })); // ["err", undefined]
+ * ```
+ */
+export function attempt<T, E>(fn: () => T): Result<T, E> {
+  try {
+    return [undefined, fn()];
+  } catch (e) {
+    return [e, undefined];
+  }
+}

attempt_test.ts

@@ -0,0 +1,15 @@
+import { test } from "@cross/test";
+import { assertEquals } from "@std/assert";
+import { attempt } from "./attempt.ts";
+
+test("attempt should return a Success<T> when the function is successful", () => {
+  const result = attempt(() => 1);
+  assertEquals(result, [undefined, 1]);
+});
+
+test("attempt should return a Failure<E> when the function is failed", () => {
+  const result = attempt(() => {
+    throw "err";
+  });
+  assertEquals(result, ["err", undefined]);
+});

deno.jsonc

@@ -3,6 +3,7 @@
   "version": "0.0.0",
   "exports": {
     ".": "./mod.ts",
+    "./attempt": "./attempt.ts",
     "./error-object": "./error_object.ts",
     "./raise": "./raise.ts",
     "./try-or": "./try_or.ts",
@@ -20,12 +21,14 @@
       "LICENSE"
     ],
     "exclude": [
+      "**/*_bench.ts",
       "**/*_test.ts",
       ".*"
     ]
   },
   "imports": {
     "@core/errorutil": "./mod.ts",
+    "@core/errorutil/attempt": "./attempt.ts",
     "@core/errorutil/error-object": "./error_object.ts",
     "@core/errorutil/raise": "./raise.ts",
     "@core/errorutil/try-or": "./try_or.ts",

mod.ts

@@ -1,3 +1,4 @@
+export * from "./attempt.ts";
 export * from "./error_object.ts";
 export * from "./raise.ts";
 export * from "./try_or.ts";