DRAFT: implement sequence

src/sequence/maxByOrNull.ts

@@ -0,0 +1,14 @@
+export function maxByOrNull<T>(value: Iterable<T>, transform: (it: T) => number): T | null {
+    let maxIt!: T;
+    let max!: number;
+    let found = false;
+    for (const it of value) {
+        const val = transform(it);
+        if (found && val <= max) continue;
+        maxIt = it;
+        max = val;
+        found = true;
+    }
+    if (!found) return null;
+    return maxIt;
+}