[VIPAX-JIT]

Resolves #8282

Changes:

This PR introduces a small but important defensive check to the map() function located in src/math/calculation.js.

Currently, when start1 === stop1, the expression:

(n - start1) / (stop1 - start1)

results in a division-by-zero case. This produces Infinity or NaN, which then propagates through subsequent drawing and color computations. These invalid values are especially confusing for beginners, as this scenario frequently occurs in sketches involving sliders, dynamic ranges, or programmatically determined bounds.

This PR adds an early return when the input range collapses, defaulting the mapped value to start2. This matches the intuitive expectation that if no mapping is possible (because the source range has zero width), the target output should fall back to its lower bound. The normal behavior of map() for all valid ranges remains fully preserved.

Why this change:

• Prevents hard-to-debug NaN and Infinity values from appearing in sketches
• Eliminates a common edge case encountered by beginners
• Improves overall robustness and predictability of the math utilities
• Fully backward-compatible and does not alter any expected API behavior
• Aligns with p5.js’s mission of supporting learning, accessibility, and beginner-friendly design
• Low-risk change that improves stability without touching rendering, DOM, or WebGL subsystems

Additional Notes:

This fix is intentionally minimal and avoids introducing any behavior that would alter existing valid mappings. It simply guards an undefined mathematical case while keeping the function’s logic identical for all standard uses. No documentation or unit test changes are strictly required, as the current behavior is undefined for start1 === stop1 and this PR only stabilizes that edge condition.

PR Checklist

• npm run lint passes
• Inline reference is included / updated
• Unit tests are included / updated

[VIPAX-JIT]

Hi maintainers.. @davepagurek @perminder-17

Just checking in on this PR. It fixes a potential division-by-zero case in map() when start1 === stop1, which currently produces Infinity/NaN and can affect drawing logic.

If there’s any additional changes or improvements needed, I’ll be happy to update the PR quickly.
Thanks for your time and effort in maintaining p5.js!

[VIPAX-JIT]

Hi maintainers.. @davepagurek @perminder-17

Just checking in on this PR. It fixes a potential division-by-zero case in map() when start1 === stop1, which currently produces Infinity/NaN and can affect drawing logic.

If there’s any additional changes or improvements needed, I’ll be happy to update the PR quickly.
Thanks for your time and effort in maintaining p5.js!

[limzykenneth]

@VIPAX-JIT Please wait for assignment in the original issue before filing a PR. There are still discussions that needs to be resolved before we can decide if a PR is needed or not in this case. Thanks.

[limzykenneth]

Having the value be start2 is not desired in this case, we probably want to keep NaN as mentioned in the original issue. We can consider having an FES message instead.