Package Exports

ok-value-error-reason
ok-value-error-reason/dist/esm/index.js
ok-value-error-reason/dist/umd/index.js

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (ok-value-error-reason) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

ok-value-error-reason

An elegant way to handle exceptions from both synchronous and asynchronous functions.

Usage

By wrapping a function call with over, you get an union types Over (ok-value-error-reason) that represents the result of a function call.

import {
    over, // stand for 'ok-value-error-reason'
} from "ok-value-error-reason";

let ans = fnLetCrash(arg1); // => crash

let ans = over(fnLetCrash, arg1); // => ans is an `Over` object

Over object is either a OKValue or ErrorReason object.

export type OKValue<V> = {
    ok: true;
    value: V;
};
export type ErrorReason<R> = {
    ok: false;
    reason: R;
};

export type OVER<V, E> = OKValue<V> | ErrorReason<E>;

You can use .ok property to narrow types.

// Wrap fnReturnNumber execution so that it will return an Over object.
let ans = over<typeof fnReturnNumber, "EMPTY" | "TOO_LONG">(
    fnReturnNumber,
    arg1,
);

if (ans.ok) {
    // `ans` is an OKValue object
    console.log(ans.value); // `.value` is number
} else {
    // `ans` is an ErrorReason object
    console.error(ans.reason); // `.reason` is "EMPTY" | "TOO_LONG"
}

over is also compatible with async functions.

// async
let asyncAns = await over<typeof asyncFnReturnNumber, "EMPTY" | "TOO_LONG">(
    asyncFnReturnNumber,
    arg1,
);