repos / starfx

safe.ts

 1import type { Callable, Operation, Result } from "effection";
 2import { Err, Ok, call } from "effection";
 3
 4/**
 5 * The goal of `safe` is to wrap Operations to prevent them from raising
 6 * and error.  The result of `safe` is always a {@link Result} type.
 7 *
 8 * @example
 9 * ```ts
10 * import { safe } from "starfx";
11 *
12 * function* run() {
13 *  const results = yield* safe(fetch("api.com"));
14 *  if (result.ok) {
15 *    console.log(result.value);
16 *  } else {
17 *    console.error(result.error);
18 *  }
19 * }
20 * ```
21 */
22function isError(error: unknown): error is Error {
23  return error instanceof Error;
24}
25
26export function* safe<T>(operator: Callable<T>): Operation<Result<T>> {
27  try {
28    const value = yield* call<T>(operator as any);
29    return Ok(value);
30  } catch (error) {
31    return Err(isError(error) ? error : new Error(String(error)));
32  }
33}