The Result Monad for Error Propagation

Snippet

The Result Monad for Error Propagation

The Result pattern replaces throwing exceptions with a returned object representing either success or failure. This functional approach makes error handling explicit in the type system, forcing developers to acknowledge potential failures and making the control flow easier to trace.

snippet.js
javascript
const Success = (value) => ({ ok: true, value });
const Failure = (error) => ({ ok: false, error });
 
const safeJSON = (str) => {
  try { return Success(JSON.parse(str)); }
  catch (e) { return Failure(e.message); }
};
 
const res = safeJSON('{"key": "val"}');
if (res.ok) {
  console.log(res.value.key);
} else {
  console.error(res.error);
}

Breakdown

return Success(JSON.parse(str))

Wraps a successful computation result in a standard container object.

if (res.ok) { ... }

Forces explicit checking of the operation's outcome before accessing data.

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The Result Monad for Error Propagation

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