fix(grapher): don't offer non-plottable entities for selection

packages/@ourworldindata/grapher/src/chart/ChartInterface.ts

@@ -32,6 +32,7 @@ export interface ChartInterface {
 
     transformTable: ChartTableTransformer
     transformTableForDisplay?: ChartTableTransformer
+    transformTableForSelection?: ChartTableTransformer
 
     yAxis?: HorizontalAxis | VerticalAxis
     xAxis?: HorizontalAxis | VerticalAxis

packages/@ourworldindata/grapher/src/core/Grapher.tsx

@@ -675,16 +675,21 @@ export class Grapher
         // Depending on the chart type, the criteria for being able to select an entity are
         // different; e.g. for scatterplots, the entity needs to (1) not be excluded and
         // (2) needs to have data for the x and y dimension.
+        let table =
+            this.isScatter || this.isSlopeChart
+                ? this.tableAfterAuthorTimelineAndActiveChartTransform
+                : this.inputTable
+
+        if (!this.isReady) return table
+
+        // Some chart types (e.g. stacked area charts) choose not to show an entity
+        // with incomplete data. Such chart types define a custom transform function
+        // to ensure that the entity selector only offers entities that are actually plotted.
+        if (this.chartInstance.transformTableForSelection) {
+            table = this.chartInstance.transformTableForSelection(table)
+        }
 
-        if (this.isScatter || this.isSlopeChart)
-            // for scatter and slope charts, the `transformTable()` call takes care of removing
-            // all entities that cannot be selected
-            return this.tableAfterAuthorTimelineAndActiveChartTransform
-
-        // for other chart types, the `transformTable()` call would sometimes remove too many
-        // entities, and we want to use the inputTable instead (which should have exactly the
-        // entities where data is available)
-        return this.inputTable
+        return table
     }
 
     // If an author sets a timeline filter run it early in the pipeline so to the charts it's as if the filtered times do not exist

packages/@ourworldindata/grapher/src/lineCharts/LineChart.tsx

@@ -66,6 +66,7 @@ import {
     CoreValueType,
     isNotErrorValue,
     EntityName,
+    BlankOwidTable,
 } from "@ourworldindata/core-table"
 import {
     autoDetectSeriesStrategy,
@@ -300,6 +301,26 @@ export class LineChart
         return table
     }
 
+    transformTableForSelection(table: OwidTable): OwidTable {
+        // if entities with partial data are not plotted,
+        // make sure they don't show up in the entity selector
+        if (this.missingDataStrategy === MissingDataStrategy.hide) {
+            table = table.replaceNonNumericCellsWithErrorValues(
+                this.yColumnSlugs
+            )
+
+            const groupedByEntity = table
+                .groupBy("entityName")
+                .filter((t) => !t.hasAnyColumnNoValidValue(this.yColumnSlugs))
+
+            if (groupedByEntity.length === 0) return BlankOwidTable()
+
+            table = groupedByEntity[0].concat(groupedByEntity.slice(1))
+        }
+
+        return table
+    }
+
     @computed private get missingDataStrategy(): MissingDataStrategy {
         return this.manager.missingDataStrategy || MissingDataStrategy.auto
     }

packages/@ourworldindata/grapher/src/stackedCharts/AbstractStackedChart.tsx

@@ -24,7 +24,11 @@ import {
     StackedRawSeries,
     StackedSeries,
 } from "./StackedConstants"
-import { OwidTable, CoreColumn } from "@ourworldindata/core-table"
+import {
+    OwidTable,
+    CoreColumn,
+    BlankOwidTable,
+} from "@ourworldindata/core-table"
 import {
     autoDetectSeriesStrategy,
     autoDetectYColumnSlugs,
@@ -84,6 +88,34 @@ export class AbstractStackedChart
         return table
     }
 
+    transformTableForSelection(table: OwidTable): OwidTable {
+        // if entities with partial data are not plotted,
+        // make sure they don't show up in the entity selector
+        if (this.missingDataStrategy !== MissingDataStrategy.show) {
+            table = table
+                .replaceNonNumericCellsWithErrorValues(this.yColumnSlugs)
+                .dropRowsWithErrorValuesForAllColumns(this.yColumnSlugs)
+
+            if (this.shouldRunLinearInterpolation) {
+                this.yColumnSlugs.forEach((slug) => {
+                    table = table.interpolateColumnLinearly(slug)
+                })
+            }
+
+            const groupedByEntity = table
+                .groupBy("entityName")
+                .map((t: OwidTable) =>
+                    t.dropRowsWithErrorValuesForAnyColumn(this.yColumnSlugs)
+                )
+
+            if (groupedByEntity.length === 0) return BlankOwidTable()
+
+            table = groupedByEntity[0].concat(groupedByEntity.slice(1))
+        }
+
+        return table
+    }
+
     @computed private get missingDataStrategy(): MissingDataStrategy {
         return this.manager.missingDataStrategy || MissingDataStrategy.auto
     }