fix(to-grid/get-headers): work with rowspan=0

lib/commons/table/get-headers.js

@@ -20,7 +20,14 @@ function traverseForHeaders(headerType, position, tableGrid) {
   // adjust position by rowspan and colspan
   // subtract 1 from col/rowspan to make them 0 indexed
   const colspan = startCell.colSpan - 1;
-  const rowspan = startCell.rowSpan - 1;
+
+  // ie11 returns 1 as the rowspan value even if it's set to 0
+  const rowspanAttr = startCell.getAttribute('rowspan');
+  const rowspanValue =
+    parseInt(rowspanAttr) === 0 || startCell.rowspan === 0
+      ? tableGrid.length
+      : startCell.rowSpan;
+  const rowspan = rowspanValue - 1;
 
   const rowStart = position.y + rowspan;
   const colStart = position.x + colspan;

lib/commons/table/to-grid.js

@@ -19,7 +19,18 @@ function toGrid(node) {
 
     for (var j = 0, cellLength = cells.length; j < cellLength; j++) {
       for (var colSpan = 0; colSpan < cells[j].colSpan; colSpan++) {
-        for (var rowSpan = 0; rowSpan < cells[j].rowSpan; rowSpan++) {
+        // if [the rowSpan] value is set to 0, it extends until the
+        // end of the table section
+        // @see https://developer.mozilla.org/en-US/docs/Web/HTML/Element/td#attr-rowspan
+
+        // ie11 returns 1 as the rowspan value even if it's set to 0
+        const rowspanAttr = cells[j].getAttribute('rowspan');
+        const rowspanValue =
+          parseInt(rowspanAttr) === 0 || cells[j].rowspan === 0
+            ? rows.length
+            : cells[j].rowSpan;
+
+        for (var rowSpan = 0; rowSpan < rowspanValue; rowSpan++) {
           table[i + rowSpan] = table[i + rowSpan] || [];
           while (table[i + rowSpan][columnIndex]) {
             columnIndex++;

test/commons/table/get-headers.js

@@ -107,6 +107,22 @@ describe('table.getHeaders', function() {
     ]);
   });
 
+  it('should handle rowspan=0', function() {
+    fixture.innerHTML =
+      '<table>' +
+      '<tr><td rowspan="0"></td><th scope="col">1</th><th scope="col" id="t1">2</th></tr>' +
+      '<tr><th scope="row" id="t2"></th><td id="target"></td></tr>' +
+      '</table>';
+
+    var target = $id('target');
+
+    axe.testUtils.flatTreeSetup(fixture.firstChild);
+    assert.deepEqual(axe.commons.table.getHeaders(target), [
+      $id('t1'),
+      $id('t2')
+    ]);
+  });
+
   it('should handle headers attribute', function() {
     fixture.innerHTML =
       '<table>' +

test/commons/table/to-grid.js

@@ -70,6 +70,21 @@ describe('table.toGrid', function() {
     ]);
   });
 
+  it('should handle rowspan=0', function() {
+    fixture.innerHTML =
+      '<table>' +
+      '<tr><td id="t1">2</td><td rowspan="0" id="t2">ok</td><td id="t3"></td></tr>' +
+      '<tr><td id="t4">4</td><td id="t5">5</td></tr>' +
+      '</table>';
+
+    var target = fixture.querySelector('table');
+
+    assert.deepEqual(axe.commons.table.toGrid(target), [
+      [$id('t1'), $id('t2'), $id('t3')],
+      [$id('t4'), $id('t2'), $id('t5')]
+    ]);
+  });
+
   it('should insert an empty array for empty rows', function() {
     fixture.innerHTML =
       '<table>' + '<tr></tr>' + '<tr><td id="t1">ok</td></tr>' + '</table>';