fix(echarts): keep forced x-axis boundary labels from overlapping and… by PrakharAgarwal17 · Pull Request #45850 · apache/superset

PrakharAgarwal17 · 2026-10-29T15:52:37Z

SUMMARY

Forced x-axis boundary labels could overlap nearby regular ticks and lacked enough date context with Adaptive formatting.

This change:

Shows standalone daily boundary dates, such as Wed 5 Mar 2014 and Mon 17 Aug 2026.
Reserves space for both boundary labels, hiding regular ticks that would collide with them.
Accounts for boundary alignment and the chart’s actual left/right padding.
Preserves explicit custom formats, the “All labels” option, and Hour-grain precision.

Regression coverage includes both boundaries, repeated formatting passes, exact spacing thresholds, narrow plots, missing or degenerate domains, custom formats, and Day/Date/Hour grains.

Implementation and tests were developed with AI assistance.

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

Before: Wed 05 lacks month/year context, and 2026 overlaps Mon 17.

After: Boundary labels include full date context, and colliding regular ticks are hidden.

TESTING INSTRUCTIONS

Create a Line Chart with Day grain and data spanning 2014-03-05 to 2026-08-17.
Select Adaptive formatting, label rotation 0, and automatic label spacing.
Resize the dashboard around 1,280–1,400px, where the final year tick would collide with the boundary label.
Confirm both boundary dates have standalone context and nearby regular ticks yield to them.

Automated validation: 217 tests passed across two focused Jest suites, plus scoped pre-commit checks including formatting, lint, and TypeScript checking.

Jest command, run from superset-frontend in the prepared test environment:

node node_modules/jest/bin/jest.js \
  --runInBand \
  --cacheDirectory=node_modules/.cache/jest \
  --runTestsByPath \
  plugins/plugin-chart-echarts/test/utils/formatters.test.ts \
  plugins/plugin-chart-echarts/test/Timeseries/transformProps.test.ts \
  --roots plugins/plugin-chart-echarts/test/utils \
  plugins/plugin-chart-echarts/test/Timeseries spec

ADDITIONAL INFORMATION

Has associated issue: Fixes Timeseries x-axis: forced first/last date labels overlap the neighboring tick label and show no month or year (7.0.0rc2) #45489
Required feature flags:
Changes UI
Includes DB Migration
- Migration is atomic, supports rollback & is backwards-compatible
- Confirm DB migration upgrade and downgrade tested
- Runtime estimates and downtime expectations provided
Introduces new feature or API
Removes existing feature or API

… show full date

codeant-ai-for-open-source · 2026-10-29T16:01:34Z

CodeAnt PR Risk

🟢 Low Risk

The PR appears safe to merge; no actionable issues were identified in the review.

Assessed commit: 8577108d8749

codecov · 2026-10-29T16:18:07Z

Codecov Report

❌ Patch coverage is 97.95918% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 84.69%. Comparing base (7ad1d7f) to head (1cbf02b).
⚠️ Report is 28 commits behind head on master.

Files with missing lines	Patch %	Lines
...hart-echarts/src/MixedTimeseries/transformProps.ts	50.00%	2 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##           master   #45850   +/-   ##
=======================================
  Coverage   84.69%   84.69%           
=======================================
  Files        3069     3069           
  Lines      205489   205573   +84     
  Branches    48314    48361   +47     
=======================================
+ Hits       174035   174119   +84     
  Misses      28164    28164           
  Partials     3290     3290

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villebro · 2026-10-30T00:02:58Z

@sadpandajoe are we ok to merge? This one is going into 7.0.0rc3

sadpandajoe · 2026-10-30T00:28:55Z

-          TIMESERIES_CONSTANTS.xAxisLabelMinGapPx
+      ((domainMin !== undefined &&
+        domainMax !== undefined &&
+        value >= domainMin &&


domainMin/domainMax and pixelsPerMs are fixed to the full data extent when the formatter is built, so after a zoom the reservation still protects boundary labels that are no longer on screen. Example: daily data Jan 1 2026–Jan 1 2027, 400px plot, %Y-%m-%d; zoom to Jan 10–Mar 1. Jan 10 is ~9px from domainMin in full-domain scale, well under the reserved boundary width, so every visible tick (including both zoom edges) formats to '' and the axis is blank, where before it kept Jan 10. Should the reservation be skipped (or computed from the visible extent) when the boundary label isn't within the zoomed range?

Thanks for pointing out , I'll look into this issue and try to reproduce it locally first then fix it

This still reproduces at the current head: ECharts keeps calling this same formatter for the zoomed ticks, so with daily data Jan 1 2026–Jan 1 2027, a 400px plot and %Y-%m-%d, zooming to Jan 10–Mar 1 returns '' for all 10 visible ticks, because the reserved width belongs to the off-screen full-range boundary labels. Could the reservation apply only when a boundary is actually in view, or be skipped once dataZoom narrows the range? A test that dispatches a dataZoom to a sub-range and asserts the visible labels are not all empty would pin it.

Thanks for the detailed reproduction. The formatter now uses the visible axis extent and actual plot width, so off-screen boundaries no longer reserve space after zooming.

I also added a regression test using a real ECharts dataZoom action for the exact 400px, Jan 10–Mar 1 case. It checks the rendered endpoint labels after zooming, panning, and resetting. The test passes locally.

sadpandajoe · 2026-10-30T07:06:50Z

-          Math.max(width - 2 * TIMESERIES_CONSTANTS.gridOffsetLeft, 0),
+          Math.max(width - padding.left - padding.right, 0),
          showAllLabels,
+          getTooltipTimeFormatter(boundaryTimeFormat, resolvedTimeGrain),


On a narrow chart the two full-date boundary labels can now collide: a 180px-wide Day-grain chart spanning Mar 5 2014–Aug 17 2026 renders Wed 5 Mar 2014 and Mon 17 Aug 2026 overlapping by roughly 69px (before this change the short Wed 05 / Mon 17 stayed separate), and the spacing check never blanks a boundary label while hideOverlap is off. Should the full-date format fall back to the short one when both boundary labels don't fit in the plot width?

Addressed this as well. When both full-date boundary labels cannot fit on one row, the last label moves to a second row, preserving the standalone date context.

Added a regression test for the exact 180px chart that checks both dates remain inside the canvas without overlapping. Also verified it manually in the browser.

netlify · 2026-10-30T11:39:02Z

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sfirke · 2026-10-30T16:48:38Z

I deployed this to my test environment and it looks good to me from a user acceptance testing (UAT) perspective. I did not review the code, just manual QA. Here's what the chart from my bug report looks like now:

The front/end dates change dynamically as you drag the zoom slider, which is pretty slick.

fix(echarts): keep forced x-axis boundary labels from overlapping and…

6052c39

… show full date

pull-request-size Bot added the size/L label Oct 29, 2026

github-actions Bot added plugins risk:chart-metadata labels Oct 29, 2026

test(echarts): cover axis formatter fallback branches

8ccc96d

sadpandajoe requested review from rusackas, sadpandajoe and sfirke October 29, 2026 18:36

sadpandajoe reviewed Oct 29, 2026

View reviewed changes

Comment thread superset-frontend/plugins/plugin-chart-echarts/src/utils/formatters.ts Resolved

Comment thread superset-frontend/plugins/plugin-chart-echarts/test/Timeseries/transformProps.test.ts Resolved

fix(echarts): preserve ticks outside the primary data domain

b39cd31

sadpandajoe reviewed Oct 30, 2026

View reviewed changes

fix(echarts): keep boundary labels readable while zooming

6a30305

pull-request-size Bot added size/XL and removed size/L labels Oct 30, 2026

fix(echarts): read custom tick values from typed label options

8577108

added new tests

1cbf02b

pull-request-size Bot added size/XXL and removed size/XL labels Oct 30, 2026

PrakharAgarwal17 requested a review from sadpandajoe October 30, 2026 13:15

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fix(echarts): keep forced x-axis boundary labels from overlapping and… - #45850

fix(echarts): keep forced x-axis boundary labels from overlapping and…#45850
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PrakharAgarwal17 commented Oct 29, 2026

SUMMARY

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

TESTING INSTRUCTIONS

ADDITIONAL INFORMATION

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