interface: add concrete instances of VirtualScroller

pkg/interface/src/views/components/GraphScroller.tsx

@@ -0,0 +1,27 @@
+import { GraphNode } from '@urbit/api';
+import bigInt, { BigInteger } from 'big-integer';
+import React from 'react';
+import VirtualScroller, { VirtualScrollerProps } from './VirtualScroller';
+
+type GraphScrollerProps = Omit<
+  VirtualScrollerProps<BigInteger, GraphNode>,
+  'keyEq' | 'keyToString' | 'keyBunt'
+>;
+
+const keyEq = (a: BigInteger, b: BigInteger) => a.eq(b);
+const keyToString = (a: BigInteger) => a.toString();
+
+export const GraphScroller = React.forwardRef<
+  VirtualScroller<BigInteger, GraphNode>,
+  GraphScrollerProps
+>((props, ref) => {
+  return (
+    <VirtualScroller
+      ref={ref}
+      {...props}
+      keyEq={keyEq}
+      keyToString={keyToString}
+      keyBunt={bigInt.zero}
+    />
+  );
+});

pkg/interface/src/views/components/ThreadScroller.tsx

@@ -0,0 +1,48 @@
+import { BigInteger } from 'big-integer';
+import React from 'react';
+import VirtualScroller, { VirtualScrollerProps } from './VirtualScroller';
+
+import { arrToString } from '@urbit/api/lib/BigIntArrayOrderedMap';
+import { FlatGraphNode } from '@urbit/api';
+
+type ThreadScrollerProps = Omit<
+  VirtualScrollerProps<BigInteger[], FlatGraphNode>,
+  'keyEq' | 'keyToString' | 'keyBunt'
+>;
+
+export function keyEq(a: BigInteger[], b: BigInteger[]) {
+  const aLen = a.length;
+  const bLen = b.length;
+
+  if (aLen === bLen) {
+    let i = 0;
+    while (i < aLen && i < bLen) {
+      if (a[i].eq(b[i])) {
+        if (i === aLen - 1) {
+          return true;
+        }
+        i++;
+      } else {
+        return false;
+      }
+    }
+  }
+
+  return false;
+}
+const keyBunt = [];
+
+export const ThreadScroller = React.forwardRef<
+  VirtualScroller<BigInteger[], FlatGraphNode>,
+  ThreadScrollerProps
+>((props: ThreadScrollerProps, ref) => {
+  return (
+    <VirtualScroller<BigInteger[], FlatGraphNode>
+      ref={ref}
+      {...props}
+      keyEq={keyEq}
+      keyToString={arrToString}
+      keyBunt={keyBunt}
+    />
+  );
+});