Lit Example: Column Sizing

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import { customElement } from 'lit/decorators.js'
import { LitElement, html } from 'lit'
import { repeat } from 'lit/directives/repeat.js'
import {
  ColumnDef,
  TableController,
  columnResizingFeature,
  columnSizingFeature,
  flexRender,
  tableFeatures,
} from '@tanstack/lit-table'
import { Person, makeData } from './makeData'

const _features = tableFeatures({
  columnSizingFeature,
  columnResizingFeature,
})

const columns: Array<ColumnDef<typeof _features, Person>> = [
  {
    accessorKey: 'firstName',
    cell: (info) => info.getValue(),
  },
  {
    accessorFn: (row) => row.lastName,
    id: 'lastName',
    cell: (info) => info.getValue(),
    header: () => html`<span>Last Name</span>`,
  },
  {
    accessorKey: 'age',
    header: () => 'Age',
  },
  {
    accessorKey: 'visits',
    header: () => html`<span>Visits</span>`,
  },
  {
    accessorKey: 'status',
    header: 'Status',
  },
  {
    accessorKey: 'progress',
    header: 'Profile Progress',
  },
  {
    accessorKey: 'rank',
    header: 'Rank',
  },
  {
    accessorKey: 'createdAt',
    header: 'Created At',
  },
]

const data: Array<Person> = makeData(1000)

@customElement('lit-table-example')
class LitTableExample extends LitElement {
  private tableController = new TableController<typeof _features, Person>(this)

  protected render() {
    const table = this.tableController.table(
      {
        _features,
        _rowModels: {},
        data,
        columns,
        columnResizeMode: 'onChange',
        columnResizeDirection: 'ltr',
        debugTable: true,
        debugHeaders: true,
        debugColumns: true,
      },
      (state) => ({
        columnSizing: state.columnSizing,
        columnResizing: state.columnResizing,
      }),
    )

    return html`
      <table style="width: ${table.getCenterTotalSize()}px">
        <thead>
          ${repeat(
            table.getHeaderGroups(),
            (headerGroup) => headerGroup.id,
            (headerGroup) => html`
              <tr>
                ${headerGroup.headers.map(
                  (header) => html`
                    <th
                      colspan="${header.colSpan}"
                      style="width: ${header.getSize()}px"
                    >
                      ${flexRender(
                        header.column.columnDef.header,
                        header.getContext(),
                      )}
                      ${header.isPlaceholder
                        ? null
                        : html`<div
                            class="resizer ${table.options
                              .columnResizeDirection} ${header.column.getIsResizing()
                              ? 'is-resizing'
                              : ''}"
                            @dblclick="${() => header.column.resetSize()}"
                            @mousedown="${header.getResizeHandler()}"
                            @touchstart="${header.getResizeHandler()}"
                          />`}
                    </th>
                  `,
                )}
              </tr>
            `,
          )}
        </thead>
        <tbody>
          ${table
            .getRowModel()
            .rows.slice(0, 10)
            .map(
              (row) => html`
                <tr>
                  ${row
                    .getAllCells()
                    .map(
                      (cell) => html`
                        <td>
                          ${flexRender(
                            cell.column.columnDef.cell,
                            cell.getContext(),
                          )}
                        </td>
                      `,
                    )}
                </tr>
              `,
            )}
        </tbody>
      </table>
      <pre>${JSON.stringify(table.state, null, 2)}</pre>
      <style>
        * {
          font-family: sans-serif;
          font-size: 14px;
          box-sizing: border-box;
        }

        table {
          border: 1px solid lightgray;
          border-collapse: collapse;
        }

        tbody {
          border-bottom: 1px solid lightgray;
        }

        th,
        td {
          border-bottom: 1px solid lightgray;
          border-right: 1px solid lightgray;
          padding: 2px 4px;
        }

        th {
          padding: 2px 4px;
          position: relative;
          font-weight: bold;
          text-align: center;
          height: 30px;
        }

        tfoot {
          color: gray;
        }

        tfoot th {
          font-weight: normal;
        }
        .resizer {
          position: absolute;
          top: 0;
          height: 100%;
          width: 5px;
          background: rgba(0, 0, 0, 0.5);
          cursor: col-resize;
          user-select: none;
          touch-action: none;
        }

        .resizer.ltr {
          right: 0;
        }

        .resizer.rtl {
          left: 0;
        }

        .resizer.is-resizing {
          background: blue;
          opacity: 1;
        }

        @media (hover: hover) {
          .resizer {
            opacity: 0;
          }

          *:hover > .resizer {
            opacity: 1;
          }
        }
      </style>
    `
  }
}