Skip to main content

Function: isErr()

isErr<T, E>(result): result is { error: E; ok: false }

Defined in: src/types/result.ts:161

Type guard for error Results.

Type Parameters​

• T

Success value type

• E extends Error

Error type

Parameters​

result​

Result<T, E>

Result to check

Returns​

result is { error: E; ok: false }

True if Result is Err, false if Ok

Remarks​

This type guard narrows the Result type, allowing safe access to the error field in TypeScript.

Example​

const result = divide(10, 0);
if (isErr(result)) {
  // TypeScript knows result.error exists
  console.error(result.error.message);
}