henningn commented on a change in pull request #28: TOBAGO-2021: Sheet should
be able to lazy load rows by scroll events
URL: https://github.com/apache/myfaces-tobago/pull/28#discussion_r387645447
##########
File path:
tobago-theme/tobago-theme-standard/src/main/resources/META-INF/resources/tobago/standard/tobago-bootstrap/_version/js/tobago-sheet.js
##########
@@ -426,7 +494,69 @@ Tobago.Sheet.setup2 = function (sheets) {
sheet.find(".tobago-sheet-cell >
input.tobago-sheet-columnSelector").click(function(event)
{event.preventDefault()});
});
- // init reload
+ // lazy load by scrolling
+ jQuery(sheets).each(function () {
+ var $sheet = jQuery(this);
+ var lazy = $sheet.data("tobago-lazy");
+
+ function getTemplate(height, columns, rowIndex) {
+ var tr = document.createElement("tr");
+ tr.dataset.tobagoRowIndex = rowIndex;
+ tr.classList.add("tobago-sheet-row");
+ tr.setAttribute("dummy", "dummy");
+ tr.style.height = height + "px";
+ var td = document.createElement("td");
+ td.classList.add("tobago-sheet-cell");
+ td.colSpan = columns;
+ tr.appendChild(td);
+ return tr;
+ }
+
+ console.time("lazy");
+ if (lazy) {
+ // prepare the sheet with some auto-created (empty) rows
+ var rows = $sheet.data("tobago-rows");
+ var rowCount = $sheet.data("tobago-row-count");
+ var $sheetBody = $sheet.find(".tobago-sheet-body");
+ var $tbody = $sheetBody.find("tbody");
+ var columns = $tbody.find("tr:first").find("td").length;
+ var height = $tbody.height() / rows;
+ var pointer = $tbody.get(0).rows[0]; // points current row
+ console.time("lazy2");
+ for (var i = 0; i < rowCount; i++) {
+ if (pointer) {
+ var rowIndex = Number(pointer.dataset.tobagoRowIndex);
+ if (i < rowIndex) {
+ var template = getTemplate(height, columns, i);
+ pointer.insertAdjacentElement("beforebegin", template);
+ } else if (i === rowIndex) {
+ pointer = pointer.nextElementSibling;
+ } else {
+ template = getTemplate(height, columns, i);
+ pointer.insertAdjacentElement("afterend", template);
+ pointer = template;
+ }
+ } else {
+ template = getTemplate(height, columns, i);
+ $tbody.get(0).insertAdjacentElement("beforeend", template);
+ pointer = template;
+ }
+ }
+ console.timeEnd("lazy2");
+
+ $sheetBody.bind("scroll", function () {
+ Tobago.Sheet.lazyCheck($sheet);
+ });
+
+ // initial
+ Tobago.Sheet.lazyCheck($sheet);
+
+ $sheet.data("tobago-lazy-initialized", true);
+ }
+ console.timeEnd("lazy");
Review comment:
dev_only missing
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