Add some comments for future fixes

Author: jassmith

packages/core/src/internal/data-grid/animation-manager.ts

@@ -55,6 +55,9 @@ export class AnimationManager {
     };
 
     private getAnimatingItems = (): StateItem[] => {
+        // this is horrible. We shoudl be mutating the array in place. The reason we don't right now is because the
+        // hoveramount is used as both the tweened value and the raw value. We should separate these two things.
+        // Then we can stop doing the allocation insanity dance.
         if (this.currentHoveredItem !== undefined) {
             return [...this.leavingItems, this.currentHoveredItem];
         }

packages/core/src/internal/data-grid/color-parser.ts

@@ -85,6 +85,7 @@ export function interpolateColors(leftColor: string, rightColor: string, val: nu
     if (val >= 1) return rightColor;
 
     // Parse to rgba returns straight alpha colors, for interpolation we want pre-multiplied alpha
+    // FIXME: This can be faster if instead of makign an array we just use variables. No memory allocation.
     const left = [...parseToRgba(leftColor)];
     left[0] = left[0] * left[3];
     left[1] = left[1] * left[3];

packages/core/src/internal/data-grid/data-grid-lib.ts

@@ -52,8 +52,9 @@ export function gridSelectionHasItem(sel: GridSelection, item: Item): boolean {
     if (sel.columns.hasIndex(col) || sel.rows.hasIndex(row)) return true;
     if (sel.current !== undefined) {
         if (itemsAreEqual(sel.current.cell, item)) return true;
-        const toCheck = [sel.current.range, ...sel.current.rangeStack];
+        const toCheck = [sel.current.range, ...sel.current.rangeStack]; // FIXME: pointless alloc
         for (const r of toCheck) {
+            // dont we have a function for this?
             if (col >= r.x && col < r.x + r.width && row >= r.y && row < r.y + r.height) return true;
         }
     }
@@ -465,7 +466,7 @@ export function getEmHeight(ctx: CanvasRenderingContext2D, fontStyle: string): n
 function truncateString(data: string, w: number): string {
     if (data.includes("\n")) {
         // new lines are rare and split is relatively expensive compared to the search
-        // it pays off to not do the split contantly.
+        // it pays off to not do the split contantly. More accurately... it pays off not to run the regex.
         data = data.split(/\r?\n/, 1)[0];
     }
     const max = w / 4; // no need to round, slice will just truncate this