Fixed htmlToGridSettings helper (#7315)

* #7311 - Fixes throwing errors if a table has no rows in htmlToGridSettings helper. Adds test spec for that behaviour.

* #7311 - Adds CHANGELOG entry. Adjusts code after linter check.

CHANGELOG.md

@@ -13,6 +13,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Fixed
 - Fixed a problem with data being pasted with an offset compensating the number of previously hidden rows/columns. [#6742](https://github.com/handsontable/handsontable/issues/6742)
 - Fixed an issue the container not being updated after trimming rows. [#7241](https://github.com/handsontable/handsontable/issues/7241)
+- Fixed an issue with a `htmlToGridSettings` helper if passed `<table>` had no rows. [#7311](https://github.com/handsontable/handsontable/issues/7311)
 - Fixed an issue where sorting indicator moved incorrectly when column was added. [#6397](https://github.com/handsontable/handsontable/issues/6397)
 - Fixed a bug, where untrimming previously trimmed rows would sometimes result in the table instance not refreshing its height, leaving the row headers not properly rendered. [#6276](https://github.com/handsontable/handsontable/issues/6276)
 - Fix a problem when `event.target`'s parent in the `mouseover` event was not defined, the table threw an error when hovering over row/column headers. [#6926](https://github.com/handsontable/handsontable/issues/6926)

src/utils/parseTable.js

@@ -195,7 +195,8 @@ export function htmlToGridSettings(element, rootDocument = document) {
 
   const generator = tempElem.querySelector('meta[name$="enerator"]');
   const hasRowHeaders = checkElement.querySelector('tbody th') !== null;
-  const countCols = Array.from(checkElement.querySelector('tr').cells)
+  const trElement = checkElement.querySelector('tr');
+  const countCols = !trElement ? 0 : Array.from(trElement.cells)
     .reduce((cols, cell) => cols + cell.colSpan, 0) - (hasRowHeaders ? 1 : 0);
   const fixedRowsBottom = checkElement.tFoot && Array.from(checkElement.tFoot.rows) || [];
   const fixedRowsTop = [];

test/unit/utils/parseTable.spec.js

@@ -107,6 +107,16 @@ describe('htmlToGridSettings', () => {
     expect(config.data.toString()).toBe('A3,B3,C3,A4,B4,C4,A5,B5,C5,A6,B6,C6');
   });
 
+  it('should parse an empty HTML table to an empty config object', () => {
+    const tableInnerHTML = [
+      '<table><tbody>',
+      '</tbody></table>',
+    ].join('');
+    const config = htmlToGridSettings(tableInnerHTML);
+
+    expect(config).toEqual({});
+  });
+
   it('should parse data with special characters', () => {
     const tableInnerHTML = [
       '<table><tbody>',