refactor(WebGL): remove support for WebGL1

Sources/Common/Core/CellArray/index.js

@@ -106,7 +106,16 @@ function vtkCellArray(publicAPI, model) {
       cellPointIds = cell;
     }
     const cellId = publicAPI.getNumberOfCells();
-    publicAPI.insertNextTuples([cellPointIds.length, ...cellPointIds]);
+    // Build the [count, ...pointIds] record without the spread operator, which
+    // would walk the iterator protocol and allocate an extra intermediate for
+    // every inserted cell.
+    const numberOfPoints = cellPointIds.length;
+    const cellRecord = new Array(numberOfPoints + 1);
+    cellRecord[0] = numberOfPoints;
+    for (let i = 0; i < numberOfPoints; ++i) {
+      cellRecord[i + 1] = cellPointIds[i];
+    }
+    publicAPI.insertNextTuples(cellRecord);
     // By computing the number of cells earlier, we made sure that numberOfCells is defined
     ++model.numberOfCells;
     if (model.cellSizes != null) {

Sources/Common/DataModel/CellLinks/index.js

@@ -105,12 +105,13 @@ function vtkCellLinks(publicAPI, model) {
    * will be built.
    */
   publicAPI.allocate = (numLinks, ext = 1000) => {
-    model.array = Array(numLinks)
-      .fill()
-      .map(() => ({
-        ncells: 0,
-        cells: null,
-      }));
+    // Populate in a single pass. Array(n).fill().map() walks the array three
+    // times (allocate sparse, fill, map) before producing the link objects.
+    const array = new Array(numLinks);
+    for (let i = 0; i < numLinks; ++i) {
+      array[i] = { ncells: 0, cells: null };
+    }
+    model.array = array;
     model.extend = ext;
     model.maxId = -1;
   };