apache/superset

Percentage number formatting in table not working on very small numbers in 5.0.0

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#36189 opened on Nov 19, 2025

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 (7 comments) (1 reaction) (0 assignees)TypeScript (72,837 stars) (17,291 forks)batch import
good first issueviz:charts:table🦾 ai-candidate

Description

Bug description

Percentage formatting for very small numbers is not applied. The result of attempts to format very small numbers as percentages is that no format is applied and the raw number is returned.

It seems what triggers this is a case in which some of the numbers are very small, but non-zero. If so, all formatting breaks for the column and even larger numbers are not formatted correctly.

E.g. -0.00001229 with D3 format .8% and Small number format .8% will just return the raw value. -0.00001229.

It doesn't matter what percentage format is applied. It fails if the attempted format is .4% or .2% as well.

Here's a link to the Slack conversation I had about this with the AI bots: https://apache-superset.slack.com/archives/C072KSLBTC1/p1763566767804459

There is mention of similar issues with number/currency formatting but nothing relating to percentage formatting specifically.

Screenshots/recordings

No response

Superset version

master / latest-dev

Python version

3.9

Node version

16

Browser

Chrome

Additional context

No response

Checklist

  • I have searched Superset docs and Slack and didn't find a solution to my problem.
  • I have searched the GitHub issue tracker and didn't find a similar bug report.
  • I have checked Superset's logs for errors and if I found a relevant Python stacktrace, I included it here as text in the "additional context" section.

Contributor guide

Tech stack
typescriptreact
Domain
frontendanalytics
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
fresh
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
Basic knowledge of D3 number formattingFamiliarity with Superset frontend codebase
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
70
Research direction
Investigate the number formatting logic in Superset, likely in frontend utility files. The issue mentions D3 format strings (e.g., '.8%') and small numbers. Check if the problem is in the formatting function itself or in how Superset handles very small numeric values. Look for similar past issues in the repository and the linked Slack conversation for additional context. The fix likely involves adjusting the threshold or precision handling for percentages.