fix(@stdlib/string/base/atob): guard global atob reference for Node <16

[Planeshifter]

Description

What is the purpose of this pull request?

This pull request:

• Fixes linux_test (Node.js v12/v14 legs), which has failed on develop every scheduled run for the past month with ReferenceError: atob is not defined in lib/node_modules/@stdlib/string/base/atob/lib/global.js. Root cause: the file exported a bare reference to the global atob identifier. Under 'use strict', that throws a ReferenceError at evaluation time on any JS engine lacking atob as a global — Node.js only added atob/btoa as globals in v16.0.0. Because lib/index.js unconditionally requires ./main.js (which requires ./global.js) before ever checking hasAtobSupport(), simply require('@stdlib/string/base/atob') crashed on Node <16, defeating the package's own polyfill fallback.
• Guards the reference with typeof atob === 'function', mirroring the identical pattern already used by this package's own dependency, @stdlib/assert/has-atob-support/lib/atob.js. typeof on an undeclared identifier evaluates to 'undefined' rather than throwing, so the module now loads safely on Node <16 and correctly falls back to the polyfill. Behavior on Node >=16 is unchanged.

Questions

Any questions for reviewers of this pull request?

No.

Other

Any other information relevant to this pull request? This may include screenshots, references, and/or implementation notes.

Failing run: https://github.com/stdlib-js/stdlib/actions/runs/29241732795 (Node.js v12/v14 legs; the v16 leg in the same run fails separately, tracked in a different PR).

Symptom: ReferenceError: atob is not defined at lib/node_modules/@stdlib/string/base/atob/lib/global.js:23.

Validation: manually verified in a Node.js v22 sandbox (package installation was not available in this environment, so make lint-pkg/the package test command could not be run directly):

• require('.../lib/global.js') with atob present returns the native function unchanged and decodes correctly.
• delete globalThis.atob; require('.../lib/global.js') no longer throws (previously threw immediately).
• delete globalThis.atob; require('@stdlib/string/base/atob') now correctly falls back to the polyfill and decodes 'SGVsbG8sIHdvcmxk' to 'Hello, world'.

Reviewed in three passes: correctness (confirmed the fix eliminates the require-time throw on Node <16 while leaving Node >=16 behavior identical; confirmed no other unguarded global reference remains in the package's require chain), regression scope (confirmed this is the only file changed; confirmed no other package imports lib/global.js directly; confirmed main.js's exported function is only ever invoked when hasAtobSupport() is true, so behavior for real callers is unchanged), and style/conventions (confirmed the pattern matches has-atob-support/lib/atob.js; confirmed commit type fix(@stdlib/string/base/atob) is correct per docs/style-guides/git/README.md).

Reviewer notes

Non-blocking: the fallback value uses void 0 where the mirrored has-atob-support/lib/atob.js uses null. Both are falsy and produce identical behavior on the unsupported path (the value is never read — main.js's exported function is never invoked when hasAtobSupport() is false), so this was left as-is rather than forcing an exact literal match.

Checklist

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

• Read, understood, and followed the contributing guidelines.

AI Assistance

When authoring the changes proposed in this PR, did you use any kind of AI assistance?

• Yes
• No

If you answered "yes" above, how did you use AI assistance?

• Code generation (e.g., when writing an implementation or fixing a bug)
• Test/benchmark generation
• Documentation (including examples)
• Research and understanding

Disclosure

If you answered "yes" to using AI assistance, please provide a short disclosure indicating how you used AI assistance. This helps reviewers determine how much scrutiny to apply when reviewing your contribution. Example disclosures: "This PR was written primarily by Claude Code." or "I consulted ChatGPT to understand the codebase, but the proposed changes were fully authored manually by myself.".

This PR was written primarily by Claude Code, investigating a GitHub Actions run failure and proposing a minimal source fix.

---

@stdlib-js/reviewers

---

Generated by Claude Code

[stdlib-bot]

Coverage Report

Package	Statements	Branches	Functions	Lines
string/base/atob	$\\color{green}217/217$ $\\color{green}+0.00\\%$	$\\color{red}11/12$ $\\color{green}+0.00\\%$	$\\color{green}2/2$ $\\color{green}+0.00\\%$	$\\color{green}217/217$ $\\color{green}+0.00\\%$

The above coverage report was generated for the changes in this PR.

[kgryte]

I believe this is a duplicate PR.

[Planeshifter]

Confirmed — #13329 already proposes the identical fix (same file, same typeof atob === 'function' guard). Closing this in favor of that one.

---

Generated by Claude Code