fix: alerts list --limit/--offset reject invalid input instead of silently misbehaving (#578)

[ygd58]

Fixes #578.

Problem

nansen alerts list --limit/--offset silently misbehaved instead of erroring on bad input, which is dangerous for a command whose whole audience is scripts and agents:

• if (options.offset) / if (options.limit) treat 0 as falsy, so --limit 0 and --offset 0 were silently ignored (treated as "not set") instead of honored.
• Number("abc") is NaN, and Array.prototype.slice coerces a NaN argument to 0 — so --offset abc silently became a no-op and --limit abc silently returned zero results, with no error telling the caller their input wasn't a number.
• A negative --offset (e.g. -1) was accepted and fed straight into slice(), which treats negative indices as "from the end" — silently returning the wrong records instead of rejecting the input.

Fix

--limit and --offset are now validated as non-negative integers (checked with Number.isInteger, not just presence), matching the strict client-side validation convention already used elsewhere in the CLI (e.g. parseSlippageBps in bridge.js, buildPagination in query-options.js). Invalid input now throws a NansenError with ErrorCode.INVALID_PARAMS and a message naming the bad value, consistent with how this same handler already rejects --enabled --disabled together.

0 is now correctly distinguished from "unset" via !== undefined checks instead of truthiness.

Testing

npm test

Test Files  1 failed | 65 passed (66)
     Tests  5 failed | 2682 passed | 16 skipped (2703)

The 5 failures are pre-existing, in src/__tests__/doctor.test.js, and reproduce identically on main without this change — they rely on chmod-based unreadable-file simulation, which doesn't apply when tests run as root. Unrelated to this fix. 7 new tests added for this fix, all passing.

npm run lint

Clean, no output.

Manual verification:

--limit 0   -> [] (previously returned everything)
--offset 0  -> full list (previously already worked, now explicit)
--limit abc -> throws "--limit must be a non-negative integer, got \"abc\"" (previously silently returned [])
--offset -1 -> throws "--offset must be a non-negative integer, got \"-1\"" (previously silently returned the last record)

Checklist

• npm test passes (output above; unrelated pre-existing failures noted)
• npm run lint passes
• New code paths have tests (7 added, covering 0, non-numeric, negative, and non-integer values for both flags)
• No console.log in core
• Error messages are actionable (name the flag and the bad value)
• Changeset added (patch — bug fix, corrects previously-silent wrong behavior)
• src/schema.json — no changes needed (no new commands/options, just stricter validation of existing ones)

[nansen-pr-reviewer]

pr-reviewer Summary for #0cc4c18

✅ No issues found

The code review completed successfully with no findings.

Review effort: 1/5 (Trivial)

Summary

This is a clean, focused bug fix that correctly addresses all three silent-failure modes described in the PR. The implementation is correct and consistent with the project's validation conventions.

The fix is sound:

• !== undefined correctly distinguishes 0 from "unset" — the core falsy-check bug is resolved.
• Number.isInteger(Number(options.offset)) catches NaN (non-numeric strings), negative values, and floats in a single guard, exactly matching patterns like buildPagination elsewhere in the codebase.
• NansenError with ErrorCode.INVALID_PARAMS and an actionable message naming the bad value is the correct error type for this handler.

Tests are thorough: 7 new test cases cover 0, non-numeric strings, negative values, and floats for both flags. The one combination not explicitly tested (offset: '2.5') is exercised by the same code path as offset: 'abc' and limit: '2.5', so coverage is sufficient.

Changeset: correctly categorized as patch, targets the right package (nansen-cli), and the description is accurate.

No issues found. Ready to merge.

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Token usage: 3,418 input, 3,118 output, 299,469 cache read, 29,694 cache write | Usage Guide

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[nansen-pr-reviewer]

Auto-approved

This PR was automatically approved because:

• Claude recommends approval
• Claude assessed this as a minimal effort change
• The effort level is within the auto-approval threshold of 2
• No high or critical issues were detected

If you have any concerns, please request a manual review.