feat: add array/base/last

[Infinage]

Description

What is the purpose of this pull request?

This pull request:

• Adds support for returning the last element of an array-like object

Related Issues

Does this pull request have any related issues?

This pull request:

• resolves [RFC]: Add @stdlib/array/base/last #858

Questions

Any questions for reviewers of this pull request?

No.

Other

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No.

Checklist

Please ensure the following tasks are completed before submitting this pull request.

• Read, understood, and followed the contributing guidelines.

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@stdlib-js/reviewers

[stdlib-bot]

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[kgryte]

LGTM. Thanks, @Infinage!

[kgryte]

LGTM. Thanks, @Infinage!

[Infinage]

Thanks for the review and the merge @kgryte! I will take better care of the edge cases and add better examples the next time. Most of the changes you did made sense. But I am just curious about these two changes:

1. Why are we multiplying the len by 2 in the createBenchmark()?

2. I am assuming this one is done for better documentation of the test results. I noticed that in the other packages we had benchmark.length.js in addition to the benchmark.js file. I wasn't able to understand the difference between those two files. However do we need to rename this file to benchmark.length.js since I see pkg+':len='+len only in files with this name?

[kgryte]

@Infinage Regarding changes,

1. You need to multiply by 2 in order for the Complex64Array to have the expected length. A complex number array has interleaved real and imaginary components. Meaning, for every complex number element, the element is comprised of a real number and a complex number which are adjacent in memory. Hence, when allocating the underlying buffer, we need to double the storage capacity.

2. Yes, in general, for benchmarks which measuring performance as a function of array length, we use the .length.js suffix to make clear that the benchmark considers input argument size when measuring perf. We use pkg+':len='+len as the file is dynamically creating benchmark functions, and we need to be able to distinguish the benchmark runs from one another in the TAP output.

For now, you do not need to rename the file. I can take care of that on my end.

Hope this answers your questions.

[Infinage]

Yes it does, thanks!