Grouping of line items

core/src/Debugger.ts

@@ -39,6 +39,7 @@ export default class Debugger {
         const outputSchema = transformer.schemaTransformer(inputSchema);
         const itemResult = transformer.transform(this.context, [...this.stageResultCache[idx - 1].items]);
         this.stageResultCache.push({
+          descriptor: transformer.descriptor,
           schema: toAnnotatedSchema(inputSchema, outputSchema),
           ...itemResult,
         });

core/src/ItemMerger.ts

@@ -0,0 +1,6 @@
+import type Item from './Item';
+
+export default interface ItemMerger {
+  groupKey: string;
+  merge(items: Item[]): Item;
+}

core/src/TransformDescriptor.ts

@@ -0,0 +1,24 @@
+import type ItemMerger from './ItemMerger';
+
+export default interface TransformDescriptor {
+  readonly requireColumns: string[];
+  readonly consumesGlobels: string[];
+  readonly producesGlobels: string[];
+  /**
+   * If this is set, the debug UI will group items and display a merged item.
+   */
+  readonly itemMerger?: ItemMerger;
+}
+
+const defaults: TransformDescriptor = {
+  requireColumns: [],
+  consumesGlobels: [],
+  producesGlobels: [],
+};
+
+export function toDescriptor(partial: Partial<TransformDescriptor>): TransformDescriptor {
+  return {
+    ...defaults,
+    ...partial,
+  };
+}

core/src/TransformerDescription.ts

@@ -1,5 +0,0 @@
-export default interface TransformerDescriptor {
-  readonly requireColumns?: string[];
-  readonly consumesGlobels?: string[];
-  readonly producesGlobels?: string[];
-}

core/src/debug/StageResult.ts

@@ -1,7 +1,9 @@
+import TransformDescriptor from '../TransformDescriptor';
 import Item from '../Item';
 import AnnotatedColumn from './AnnotatedColumn';
 
 export default interface StageResult {
+  descriptor?: TransformDescriptor;
   schema: AnnotatedColumn[];
   items: Item[];
   messages: string[];

core/src/support/ItemGroup.ts

@@ -0,0 +1,17 @@
+import { assertDefined } from '../assert';
+import type Item from '../Item';
+import type ItemMerger from '../ItemMerger';
+
+export default class ItemGroup {
+  top: Item;
+  elements: Item[];
+
+  constructor(top: Item, items: Item[] = []) {
+    this.top = top;
+    this.elements = items;
+  }
+
+  hasMany(): boolean {
+    return this.elements.length > 0;
+  }
+}

core/src/support/Page.ts

@@ -0,0 +1,6 @@
+import type ItemGroup from './ItemGroup';
+
+export default interface Page {
+  index: number;
+  itemGroups: ItemGroup[];
+}

core/src/support/itemUtils.ts

@@ -0,0 +1,55 @@
+import ItemMerger from 'src/ItemMerger';
+import Item from '../Item';
+import ItemGroup from './ItemGroup';
+import Page from './Page';
+
+type PageItemTransformer = (page: number, items: Item[]) => Item[];
+
+export function groupByPage(items: Item[]): Item[][] {
+  return items.reduce((pageItems: Item[][], item: Item) => {
+    const lastPageItems = pageItems[pageItems.length - 1];
+    if (!lastPageItems || item.page > lastPageItems[0]?.page) {
+      pageItems.push([item]);
+    } else {
+      lastPageItems.push(item);
+    }
+    return pageItems;
+  }, []);
+}
+
+export function groupByElement(items: Item[], elementName: string): Item[][] {
+  return items.reduce((groupedItems: Item[][], item: Item) => {
+    const lastGroupItems = groupedItems[groupedItems.length - 1];
+    if (!lastGroupItems || item.data[elementName] !== lastGroupItems[0]?.data[elementName]) {
+      groupedItems.push([item]);
+    } else {
+      lastGroupItems.push(item);
+    }
+    return groupedItems;
+  }, []);
+}
+
+export function transformGroupedByPage(items: Item[], groupedTransformer: PageItemTransformer): Item[] {
+  return new Array<Item>().concat(
+    ...groupByPage(items).map((pageItems) => groupedTransformer(pageItems[0].page, pageItems)),
+  );
+}
+
+export function asPages(items: Item[], itemMerger?: ItemMerger): Page[] {
+  return groupByPage(items).map((pageItems: Item[]) => {
+    let itemGroups: ItemGroup[];
+    if (itemMerger) {
+      itemGroups = groupByElement(pageItems, itemMerger.groupKey).map((groupItems) => {
+        if (groupItems.length > 1) {
+          const top = itemMerger.merge(groupItems);
+          return new ItemGroup(top, groupItems);
+        } else {
+          return new ItemGroup(groupItems[0]);
+        }
+      });
+    } else {
+      itemGroups = pageItems.map((item) => new ItemGroup(item));
+    }
+    return { index: pageItems[0].page, itemGroups } as Page;
+  });
+}

core/src/transformer/AdjustHeight.ts

@@ -3,7 +3,7 @@ import Item from '../Item';
 import ItemResult from '../ItemResult';
 import ItemTransformer from './ItemTransformer';
 import TransformContext from './TransformContext';
-import { transformGroupedByPage } from './transformerUtils';
+import { transformGroupedByPage } from '../support/itemUtils';
 
 export default class AdjustHeight extends ItemTransformer {
   constructor() {

core/src/transformer/CompactLines.ts

@@ -2,7 +2,7 @@ import Item from '../Item';
 import ItemResult from '../ItemResult';
 import ItemTransformer from './ItemTransformer';
 import TransformContext from './TransformContext';
-import { transformGroupedByPage } from './transformerUtils';
+import { transformGroupedByPage } from '../support/itemUtils';
 
 export default class CompactLines extends ItemTransformer {
   constructor() {
@@ -11,6 +11,10 @@ export default class CompactLines extends ItemTransformer {
       'Combines items on the same y-axis',
       {
         requireColumns: ['str', 'y'],
+        itemMerger: {
+          groupKey: 'line',
+          merge: mergeLineItems,
+        },
       },
       (incomingSchema) => {
         return incomingSchema.reduce((schema, column) => {
@@ -41,3 +45,25 @@ export default class CompactLines extends ItemTransformer {
     };
   }
 }
+
+function mergeLineItems(items: Item[]): Item {
+  const page = items[0].page;
+  const line = items[0].data['line'];
+  const str = items.map((item) => item.data['str']).join(' ');
+  const x = Math.min(...items.map((item) => item.data['x']));
+  const y = Math.min(...items.map((item) => item.data['y']));
+  const width = items.reduce((sum, item) => sum + item.data['width'], 0);
+  const height = Math.max(...items.map((item) => item.data['height']));
+  const fontNames = [...new Set(items.map((item) => item.data['fontName']))];
+  const directions = [...new Set(items.map((item) => item.data['dir']))];
+  return new Item(page, {
+    str,
+    line,
+    x,
+    y,
+    width,
+    height,
+    fontName: fontNames,
+    dir: directions,
+  });
+}

core/src/transformer/ItemTransformer.ts

@@ -1,4 +1,4 @@
-import type TransformerDescriptor from '../TransformerDescription';
+import TransformDescriptor, { toDescriptor } from '../TransformDescriptor';
 import type TransformContext from './TransformContext';
 import type Item from '../Item';
 import type ItemResult from '../ItemResult';
@@ -11,25 +11,18 @@ type SchemaTransformer = (incomingSchema: string[]) => string[];
 export default abstract class ItemTransformer {
   readonly name: string;
   readonly description: string;
-  readonly descriptor: TransformerDescriptor;
+  readonly descriptor: TransformDescriptor;
   readonly schemaTransformer: SchemaTransformer;
 
   constructor(
     name: string,
     description: string,
-    descriptor: TransformerDescriptor,
+    descriptorPartial: Partial<TransformDescriptor>,
     schemaTransformer: SchemaTransformer = (schema) => schema,
   ) {
     this.name = name;
     this.description = description;
-    this.descriptor = {
-      ...{
-        consumesGlobels: [],
-        producesGlobels: [],
-        requireColumns: [],
-      },
-      ...descriptor,
-    };
+    this.descriptor = toDescriptor(descriptorPartial);
     this.schemaTransformer = schemaTransformer;
   }
 

core/src/transformer/transformerUtils.ts

@@ -1,19 +0,0 @@
-import Item from '../Item';
-
-type PageItemTransformer = (page: number, items: Item[]) => Item[];
-
-export function transformGroupedByPage(items: Item[], groupedTransformer: PageItemTransformer) {
-  return new Array<Item>().concat(
-    ...items
-      .reduce((pageItems: Item[][], item: Item) => {
-        const lastPageItems = pageItems[pageItems.length - 1];
-        if (!lastPageItems || item.page > lastPageItems[0]?.page) {
-          pageItems.push([item]);
-        } else {
-          lastPageItems.push(item);
-        }
-        return pageItems;
-      }, [])
-      .map((pageItems) => groupedTransformer(pageItems[0].page, pageItems)),
-  );
-}

core/test/Debugger.test.ts

@@ -1,7 +1,7 @@
 import Debugger from 'src/Debugger';
 import Item from 'src/Item';
 import ItemTransformer from 'src/transformer/ItemTransformer';
-import TransformerDescriptor from 'src/TransformerDescription';
+import TransformDescriptor from 'src/TransformDescriptor';
 import TransformContext from 'src/transformer/TransformContext';
 import ItemResult from 'src/ItemResult';
 import ColumnAnnotation from 'src/debug/ColumnAnnotation';
@@ -9,7 +9,7 @@ import AnnotatedColumn from 'src/debug/AnnotatedColumn';
 
 class TestTransformer extends ItemTransformer {
   items: Item[];
-  constructor(name: string, descriptor: TransformerDescriptor, outputSchema: string[], items: Item[]) {
+  constructor(name: string, descriptor: Partial<TransformDescriptor>, outputSchema: string[], items: Item[]) {
     super(name, `Description for ${name}`, descriptor, (incomingSchema) => outputSchema);
     this.items = items;
   }
@@ -30,7 +30,7 @@ test('basic debug', async () => {
   const trans1Items = parsedItems.map((item) => item.withData({ C: `c=${item.value('A')}+${item.value('B')}` }));
 
   const transformers = [new TestTransformer('Trans1', trans1Desc, trans1Schema, trans1Items)];
-  const debug = new Debugger(parsedSchema, parsedItems, { pageViewports: [] }, transformers);
+  const debug = new Debugger(parsedSchema, parsedItems, { fontMap: new Map(), pageViewports: [] }, transformers);
 
   expect(debug.stageNames).toEqual(['Parse Result', 'Trans1']);
   expect(debug.stageResults(0).schema).toEqual(parsedSchema.map((column) => ({ name: column })));
@@ -47,7 +47,7 @@ describe('build schemas', () => {
 
   function calculateSchema(inputSchema: string[], outputSchema: string[]): AnnotatedColumn[] {
     const transformers = [new TestTransformer('Trans1', {}, outputSchema, items)];
-    const debug = new Debugger(inputSchema, items, { pageViewports: [] }, transformers);
+    const debug = new Debugger(inputSchema, items, { fontMap: new Map(), pageViewports: [] }, transformers);
     return debug.stageResults(1).schema;
   }
 

core/test/PdfPipeline.test.ts

@@ -1,4 +1,4 @@
-import TransformerDescriptor from 'src/TransformerDescription';
+import TransformDescriptor from 'src/TransformDescriptor';
 import Item from 'src/Item';
 import ItemResult from 'src/ItemResult';
 import ItemTransformer from 'src/transformer/ItemTransformer';
@@ -9,7 +9,7 @@ import * as fs from 'fs';
 import PdfPipeline from 'src/PdfPipeline';
 
 class TestSchemaTransformer extends ItemTransformer {
-  constructor(name: string, descriptor: TransformerDescriptor, outputSchema: string[] | undefined = undefined) {
+  constructor(name: string, descriptor: Partial<TransformDescriptor>, outputSchema: string[] | undefined = undefined) {
     if (outputSchema) {
       super(name, `Description for ${name}`, descriptor, (_) => outputSchema);
     } else {

core/test/support/itemUtils.test.ts

@@ -0,0 +1,112 @@
+import Item from 'src/Item';
+import Page from 'src/support/Page';
+import { groupByPage, groupByElement, transformGroupedByPage, asPages } from 'src/support/itemUtils';
+import ItemGroup from 'src/support/ItemGroup';
+import ItemMerger from 'src/ItemMerger';
+import ItemTransformer from 'src/transformer/ItemTransformer';
+
+describe('groupByPage', () => {
+  test('empty', async () => {
+    expect(groupByPage([])).toEqual([]);
+  });
+
+  test('group', async () => {
+    const pageItems = [
+      [new Item(0, { id: 1 })],
+      [new Item(1, { id: 2 }), new Item(1, { id: 3 })],
+      [new Item(2, { id: 4 })],
+    ];
+    const flattenedItems = new Array<Item>().concat(...pageItems);
+    const transformedItems = groupByPage(flattenedItems);
+    expect(transformedItems).toEqual(pageItems);
+  });
+});
+
+describe('groupByElement', () => {
+  test('empty', async () => {
+    expect(groupByElement([], 'line')).toEqual([]);
+  });
+
+  test('group', async () => {
+    const groupedItems = [
+      [new Item(0, { line: 1, id: 1 })],
+      [new Item(0, { line: 2, id: 2 }), new Item(0, { line: 2, id: 3 })],
+      [new Item(0, { line: 3, id: 4 })],
+    ];
+    const flattenedItems = new Array<Item>().concat(...groupedItems);
+    const transformedItems = groupByElement(flattenedItems, 'line');
+    expect(transformedItems).toEqual(groupedItems);
+  });
+});
+
+describe('transformGroupedByPage', () => {
+  test('empty', async () => {
+    const transformedItems = transformGroupedByPage([], () => fail("shoudln't be called"));
+    expect(transformedItems).toEqual([]);
+  });
+
+  test('pipe through', async () => {
+    const pageItems = [
+      [new Item(0, { id: 1 })],
+      [new Item(1, { id: 2 }), new Item(1, { id: 3 })],
+      [new Item(2, { id: 4 })],
+    ];
+    const flattenedItems = new Array<Item>().concat(...pageItems);
+    const transformedItems = transformGroupedByPage(flattenedItems, (page, items) => {
+      expect(items).toEqual(pageItems[page]);
+      return items;
+    });
+    expect(transformedItems).toEqual(flattenedItems);
+  });
+
+  test('change', async () => {
+    const input = [new Item(0, { v: 0 }), new Item(1, { v: 0 })];
+    const transformedItems = transformGroupedByPage(input, (_, items) => {
+      return [items[0].withData({ v: 1 })];
+    });
+    expect(transformedItems).toEqual(input.map((item) => item.withData({ v: 1 })));
+  });
+});
+
+describe('asPages', () => {
+  test('empty', async () => {
+    expect(groupByPage([])).toEqual([]);
+  });
+
+  test('no merger', async () => {
+    const pageItems = [
+      [new Item(0, { id: 1, line: 1 })],
+      [new Item(1, { id: 2, line: 1 }), new Item(1, { id: 3, line: 1 }), new Item(1, { id: 4, line: 2 })],
+      [new Item(2, { id: 5, line: 1 })],
+    ];
+    const flattenedItems = new Array<Item>().concat(...pageItems);
+    const pages = asPages(flattenedItems);
+    expect(pages).toEqual([
+      { index: 0, itemGroups: pageItems[0].map((item) => new ItemGroup(item)) },
+      { index: 1, itemGroups: pageItems[1].map((item) => new ItemGroup(item)) },
+      { index: 2, itemGroups: pageItems[2].map((item) => new ItemGroup(item)) },
+    ] as Page[]);
+  });
+
+  test('merger', async () => {
+    const pageItems = [
+      [new Item(0, { id: 1, line: 1 })],
+      [new Item(1, { id: 2, line: 1 }), new Item(1, { id: 3, line: 1 }), new Item(1, { id: 4, line: 2 })],
+      [new Item(2, { id: 5, line: 1 })],
+    ];
+    const flattenedItems = new Array<Item>().concat(...pageItems);
+    const merger: ItemMerger = { groupKey: 'line', merge: (items) => items[0] };
+    const pages = asPages(flattenedItems, merger);
+    expect(pages).toEqual([
+      { index: 0, itemGroups: pageItems[0].map((item) => new ItemGroup(item)) },
+      {
+        index: 1,
+        itemGroups: [
+          new ItemGroup(merger.merge(pageItems[1].slice(0, 2)), pageItems[1].slice(0, 2)),
+          new ItemGroup(pageItems[1][2]),
+        ],
+      },
+      { index: 2, itemGroups: pageItems[2].map((item) => new ItemGroup(item)) },
+    ] as Page[]);
+  });
+});

core/test/transformer/CompactLines.test.ts

@@ -0,0 +1,51 @@
+import Item from 'src/Item';
+import CompactLines from 'src/transformer/CompactLines';
+test('Item Merger', async () => {
+  const itemMerger = new CompactLines().descriptor.itemMerger;
+  expect(itemMerger?.groupKey).toEqual('line');
+
+  const mergedItem = itemMerger?.merge([
+    new Item(0, {
+      line: 2,
+      x: 240,
+      y: 585,
+      str: 'Dies ist eine Test-PDF',
+      fontName: 'g_d0_f2',
+      dir: 'ltr',
+      width: 108.62,
+      height: 11,
+    }),
+    new Item(0, {
+      line: 2,
+      x: 352.69,
+      y: 585,
+      str: '.',
+      fontName: 'g_d0_f2',
+      dir: 'ltr',
+      width: 3.06,
+      height: 11,
+    }),
+    new Item(0, {
+      line: 2,
+      x: 348,
+      y: 588,
+      str: '1',
+      fontName: 'g_d0_f2',
+      dir: 'ltr',
+      width: 4.08,
+      height: 7.33,
+    }),
+  ]);
+  expect(mergedItem?.withoutUuid()).toEqual(
+    new Item(0, {
+      line: 2,
+      x: 240,
+      y: 585,
+      str: 'Dies ist eine Test-PDF . 1',
+      fontName: ['g_d0_f2'],
+      dir: ['ltr'],
+      width: 115.76,
+      height: 11,
+    }).withoutUuid(),
+  );
+});

core/test/transformer/transformerUtils.test.ts

@@ -1,31 +0,0 @@
-import Item from 'src/Item';
-import { transformGroupedByPage } from 'src/transformer/transformerUtils';
-
-describe('transformGroupedByPage', () => {
-  test('empty', async () => {
-    const transformedItems = transformGroupedByPage([], () => fail("shoudln't be called"));
-    expect(transformedItems).toEqual([]);
-  });
-
-  test('pipe through', async () => {
-    const pageItems = [
-      [new Item(0, { id: 1 })],
-      [new Item(1, { id: 2 }), new Item(1, { id: 3 })],
-      [new Item(2, { id: 4 })],
-    ];
-    const flattenedItems = new Array<Item>().concat(...pageItems);
-    const transformedItems = transformGroupedByPage(flattenedItems, (page, items) => {
-      expect(items).toEqual(pageItems[page]);
-      return items;
-    });
-    expect(transformedItems).toEqual(flattenedItems);
-  });
-
-  test('change', async () => {
-    const input = [new Item(0, { v: 0 }), new Item(1, { v: 0 })];
-    const transformedItems = transformGroupedByPage(input, (_, items) => {
-      return [items[0].withData({ v: 1 })];
-    });
-    expect(transformedItems).toEqual(input.map((item) => item.withData({ v: 1 })));
-  });
-});

ui/src/debug/DebugView.svelte

@@ -3,8 +3,11 @@
     import Icon from 'fa-svelte';
     import { faMapPin as pin } from '@fortawesome/free-solid-svg-icons/faMapPin';
     import { BookOpen, ArrowLeft, ArrowRight } from 'svelte-hero-icons';
+
     import type Debugger from '@core/Debugger';
     import type Item from '@core/Item';
+    import { asPages } from '../../../core/src/support/itemUtils';
+
     import Popup from '../components/Popup.svelte';
     import PageSelectionPopup from './PageSelectionPopup.svelte';
     import ItemTable from './ItemTable.svelte';
@@ -21,17 +24,9 @@
     $: stageResult = debug.stageResults(currentStage);
     $: pageIsPinned = !isNaN(pinnedPage);
     $: pagesNumbers = new Set(stageResult.items.map((item) => item.page));
+    $: pages = asPages(stageResult.items, stageResult.descriptor?.itemMerger);
     $: maxPage = Math.max(...pagesNumbers);
-    $: itemsByPage = [
-        ...stageResult.items.reduce((map, item) => {
-            if (!map.has(item.page)) {
-                map.set(item.page, []);
-            }
-            map.get(item.page).push(item);
-            return map;
-        }, new Map<number, Item[]>()),
-    ];
-    $: visiblePages = pageIsPinned ? itemsByPage.filter(([page]) => page === pinnedPage) : itemsByPage;
+    $: visiblePages = pageIsPinned ? pages.filter((page) => page.index === pinnedPage) : pages;
 </script>
 
 <div class="mx-4">
@@ -97,7 +92,7 @@
     </ul>
 
     <!-- Items -->
-    <ItemTable schema={stageResult.schema} itemsByPage={visiblePages} {maxPage} {pageIsPinned} />
+    <ItemTable schema={stageResult.schema} pages={visiblePages} {maxPage} {pageIsPinned} />
 </div>
 
 <style>

ui/src/debug/ItemTable.svelte

@@ -1,26 +1,27 @@
 <script>
     import { scale, fade } from 'svelte/transition';
-    import type Item from '@core/Item';
     import type AnnotatedColumn from '@core/debug/AnnotatedColumn';
     import ColumnAnnotation from '../../../core/src/debug/ColumnAnnotation';
     import inView from '../actions/inView';
     import { formatValue } from './formatValues';
+    import type Page from '@core/support/Page';
 
     export let schema: AnnotatedColumn[];
-    export let itemsByPage: [number, Item[]][];
+    export let pages: Page[];
     export let maxPage: number;
     export let pageIsPinned: boolean;
     let maxItemsToRenderInOneLoad = 200;
     let renderedMaxPage = 0;
+    let expandedItemGroup: { pageIndex: number; itemIndex: number };
 
-    let renderedItemsByPage: [number, Item[]][];
+    let renderedPages: Page[];
     $: {
         if (pageIsPinned) {
-            renderedItemsByPage = itemsByPage;
+            renderedPages = pages;
             renderedMaxPage = 0;
         } else {
             calculateNextPageToRenderTo();
-            renderedItemsByPage = itemsByPage.slice(0, renderedMaxPage);
+            renderedPages = pages.slice(0, renderedMaxPage);
         }
     }
 
@@ -29,16 +30,22 @@
             return;
         }
         let itemCount = 0;
-        for (let index = 0; index < itemsByPage.length; index++) {
+        for (let index = 0; index < pages.length; index++) {
             renderedMaxPage++;
-            const [_, items] = itemsByPage[index];
-            itemCount += items.length;
+            itemCount += pages[index].itemGroups.length;
             if (itemCount > maxItemsToRenderInOneLoad) {
                 break;
             }
         }
         // console.log(`Render pages 0 to ${renderedMaxPage} with ${itemCount} items`);
     }
+
+    const isExpanded = (pageIndex: number, itemIndex: number) => {
+        return expandedItemGroup?.pageIndex === pageIndex && expandedItemGroup?.itemIndex === itemIndex;
+    };
+    const toggleRow = (pageIndex: number, itemIndex: number) => {
+        expandedItemGroup = isExpanded(pageIndex, itemIndex) ? undefined : { pageIndex, itemIndex };
+    };
 </script>
 
 <!-- Item table -->
@@ -56,33 +63,53 @@
         {/each}
     </thead>
     <tbody>
-        {#each renderedItemsByPage as [pageNumber, items], pageIdx}
+        {#each renderedPages as page, pageIdx}
             <!-- Separator between pages -->
             {#if pageIdx > 0}
                 <tr class="h-5" />
             {/if}
-            {#each items as item, itemIdx}
-                <tr in:fade>
+
+            <!-- Page items -->
+            {#each page.itemGroups as itemGroup, itemIdx}
+                <tr
+                    class:expandable={itemGroup.hasMany()}
+                    class:expanded={expandedItemGroup && isExpanded(page.index, itemIdx)}
+                    in:fade>
                     <!-- Page number in first page item row -->
                     {#if itemIdx === 0}
-                        <td class="page bg-gray-50">
-                            <div>Page {pageNumber} {pageIsPinned ? '' : ' / ' + maxPage}</div>
+                        <td id="page" class="page bg-gray-50">
+                            <div>Page {page.index} {pageIsPinned ? '' : ' / ' + maxPage}</div>
                         </td>
                     {:else}
-                        <td />
+                        <td id="page" />
                     {/if}
-                    <td>{itemIdx}</td>
+                    <span class="contents" on:click={() => itemGroup.hasMany() && toggleRow(page.index, itemIdx)}>
+                        <td>{itemIdx}{itemGroup.hasMany() ? '+' : ''}</td>
                         {#each schema as column}
-                        <td class="select-all">{formatValue(item.data[column.name])}</td>
+                            <td class="select-all">{formatValue(itemGroup.top.data[column.name])}</td>
+                        {/each}
+                    </span>
+                </tr>
+
+                <!-- Expanded childs -->
+                {#if expandedItemGroup && isExpanded(page.index, itemIdx)}
+                    {#each itemGroup.elements as child, childIdx}
+                        <tr class="childs">
+                            <td id="page" />
+                            <td>{'└ ' + childIdx}</td>
+                            {#each schema as column}
+                                <td class="select-all">{formatValue(child.data[column.name])}</td>
                             {/each}
                         </tr>
                     {/each}
+                {/if}
+            {/each}
         {/each}
     </tbody>
 </table>
 
 {#if !pageIsPinned}
-    {#if renderedMaxPage < itemsByPage.length}
+    {#if renderedMaxPage < pages.length}
         <span use:inView on:intersect={({ detail }) => detail && calculateNextPageToRenderTo()} />
         <div class="my-6 text-center text-2xl">...</div>
     {:else}
@@ -113,12 +140,24 @@
         @apply bg-gray-300;
         @apply shadow;
     }
-    td:not(:first-child) {
+    td:not(#page) {
         @apply px-1;
         @apply border-b;
     }
 
-    tr:hover td:not(:first-child) {
+    tr:hover td:not(#page) {
+        @apply bg-gray-200;
+    }
+
+    tr.expandable:hover td:not(#page) {
+        @apply cursor-pointer;
+    }
+
+    tr.expanded td:not(#page) {
+        @apply bg-gray-300;
+    }
+
+    tr.childs td:not(#page) {
         @apply bg-gray-200;
     }
 </style>