Function _fnHeaderLayout

external/.datatables.js:3028–3097

* Build a layout structure for a header or footer * * @param {*} settings DataTables settings * @param {*} source Source layout array * @param {*} incColumns What columns should be included * @returns Layout array

(settings, source, incColumns)

	 * @returns Layout array
	 */
	function _fnHeaderLayout(settings, source, incColumns) {
		var row, column, cell
		var local = []
		var structure = []
		var columns = settings.aoColumns
		var columnCount = columns.length
		var rowspan, colspan

		if (!source) {
			return
		}

		// Default is to work on only visible columns
		if (!incColumns) {
			incColumns = _range(columnCount).filter(function (idx) {
				return columns[idx].bVisible
			})
		}

		// Make a copy of the master layout array, but with only the columns we want
		for (row = 0; row < source.length; row++) {
			// Remove any columns we haven't selected
			local[row] = source[row].slice().filter(function (cell, i) {
				return incColumns.includes(i)
			})

			// Prep the structure array - it needs an element for each row
			structure.push([])
		}

		for (row = 0; row < local.length; row++) {
			for (column = 0; column < local[row].length; column++) {
				rowspan = 1
				colspan = 1

				// Check to see if there is already a cell (row/colspan) covering our target
				// insert point. If there is, then there is nothing to do.
				if (structure[row][column] === undefined) {
					cell = local[row][column].cell

					// Expand for rowspan
					while (local[row + rowspan] !== undefined && local[row][column].cell == local[row + rowspan][column].cell) {
						structure[row + rowspan][column] = null
						rowspan++
					}

					// And for colspan
					while (local[row][column + colspan] !== undefined && local[row][column].cell == local[row][column + colspan].cell) {
						// Which also needs to go over rows
						for (var k = 0; k < rowspan; k++) {
							structure[row + k][column + colspan] = null
						}

						colspan++
					}

					var titleSpan = $("span.dt-column-title", cell)