fix(@stdlib/string/base/atob): guard against ReferenceError when atob global is absent

[Planeshifter]

Description

What is the purpose of this pull request?

This pull request:

• Fixes lib/node_modules/@stdlib/string/base/atob/lib/global.js: module.exports = atob; referenced the bare atob global unconditionally. Node.js only defines atob globally starting in v16; on Node.js 12/14, evaluating the undeclared identifier threw a ReferenceError at module load, not at call time. Since lib/main.js requires this module eagerly, and the package's test files require lib/main.js at top level, the crash happened before the existing hasAtobSupport()-gated tape skip logic could run, breaking the linux_test workflow's Node.js v12 and v14 jobs on every scheduled run (https://github.com/stdlib-js/stdlib/actions/runs/32710852762). Fix: guard the reference with var main = ( typeof atob === 'function' ) ? atob : null;, matching the existing idiom in @stdlib/assert/has-atob-support/lib/atob.js. require('@stdlib/string/base/atob') in production is unaffected — that path resolves through lib/index.js via hasAtobSupport() and never hits this file's bug.

Related Issues

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This pull request has the following related issues:

• None.

Questions

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No.

Other

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Diff: one file, 6 lines added, 1 removed.

No node_modules install was possible in this environment, so verification used Node's vm module to evaluate the file in a fresh V8 context: no throw and correct null fallback with atob absent from globals, correct pass-through with atob present.

Reviewed independently across correctness, regression scope, and style/conventions before opening. All three passes flagged the same non-blocking issue from an early draft: an // eslint-disable-line stdlib/no-redeclare comment was unnecessary — that rule only fires on declarations shadowing a global of the same name, and var main doesn't shadow atob — and would have tripped --report-unused-disable-directives. Removed before commit.

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• Read, understood, and followed the contributing guidelines.

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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 investigated, written, and validated by Claude Code as part of an automated CI-failure triage routine: it identified the failing linux_test jobs, traced the root cause, implemented the fix, and validated it via three independent automated review passes (correctness, regression scope, style/conventions) before opening this PR.

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Generated by Claude Code

[stdlib-bot]

Coverage Report

Package	Statements	Branches	Functions	Lines
string/base/atob	$\\color{green}217/217$ $\\color{green}+100.00\\%$	$\\color{red}11/12$ $\\color{green}+91.67\\%$	$\\color{green}2/2$ $\\color{green}+100.00\\%$	$\\color{green}217/217$ $\\color{green}+100.00\\%$

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