fix(types): narrow return type of first and last

[crishoj]

Summary

As with draw() in #153, we can narrow the return type for first() and last() in case the argument is known to be empty or non-empty.

With custom defaultValue:

Related issue, if any:

• Related: fix(types): improve draw signature for non-empty arrays #153
• Previous attempt: feat(array): narrow return type for first and last #140

For any code change,

• Related tests have been added or updated, if needed: Type-level tests added

Does this PR introduce a breaking change?

No

Calculating...

[radashi-bot]

Benchmark Results

Name	Current	Baseline	Change
first ▶︎ with non-empty array	4,021,536.87 ops/sec ±0.62%	5,004,789.13 ops/sec ±0.06% 🔗	🐢 -19.65%
first ▶︎ with empty array and a default value	4,496,299.53 ops/sec ±0.06%	5,043,634.55 ops/sec ±0.06% 🔗	🐢 -10.85%
last ▶︎ with valid input	3,942,475.39 ops/sec ±0.58%	4,900,688.46 ops/sec ±0.42% 🔗	🐢 -19.55%
last ▶︎ with empty list	4,259,555.08 ops/sec ±0.06%	4,646,235.66 ops/sec ±0.07% 🔗	🐢 -8.32%

Generally speaking, any regression ≥20% should be investigated if it wasn't to be expected.

[crishoj]

There's a new requirement for PRs that introduce new features. Without this requirement met, we won't be able to merge this.

Hi @aleclarson, I have filled out next-minor.md now (d0e722b).

[aleclarson]

@crishoj Sorry, I renamed this PR so it's a fix and not a feat anymore, which means you edited next-minor.md for nothing 😅

[crishoj]

Oh, no worries 😃

[aleclarson]

My changes have enabled first and last to return the proper type for tuples:

const val1 = first([1, 2])
//    ^? 1

const val2 = last([1, 2])
//    ^? 2

[radashi-bot]

A stable release 12.2.2 has been published to NPM. 🚀

To install:

pnpm add [email protected]

[crishoj]

Neat! Inferred type for TFirst and TLast is clever.