chore(fix): allow Result tuple to be [undefined, undefined]

[aleclarson]

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Summary

Fix isResult to return true for a [undefined, undefined] tuple. This is to handle the case where a function with a possibly undefined return value is wrapped with tryit, which may produce such a tuple.

I'm also constraining the TError type parameter of Result/Ok/Err so it must be a subtype of the built-in Error type. In other words, it no longer allows the error element to be any type. This is necessary to reduce the chance of isResult returning a false positive for certain arrays.

Note: This is a "chore" and not a "fix" because isResult hasn't been released yet.

For any code change,

• Related documentation has been updated, if needed
• Related tests have been added or updated, if needed

Does this PR introduce a breaking change?

No

Bundle impact

Status	File	Size 1	Difference (%)
M	src/typed/isResult.ts	217	+102 (+89%)
M	src/typed/isResultErr.ts	261	+102 (+64%)

Footnotes

1. Function size includes the import dependencies of the function. ↩

[github-actions]

A new beta version 12.2.0-beta.6b76988 has been published to NPM. 🚀

To install:

pnpm add radashi@12.2.0-beta.6b76988

The radashi@beta tag also includes this PR.