Implement sequence

src/sequence/minByOrNull.ts

@@ -1,14 +1,13 @@
 export function minByOrNull<T>(value: Iterable<T>, transform: (it: T) => number): T | null {
     let minIt!: T;
-    let min!: number;
-    let found = false;
+    let minVal: number | undefined;
     for (const it of value) {
         const val = transform(it);
-        if (found && val >= min) continue;
-        minIt = it;
-        min = val;
-        found = true;
+        if (minVal === undefined || val < minVal) {
+            minIt = it;
+            minVal = val;
+        }
     }
-    if (!found) return null;
+    if (minVal === undefined) return null;
     return minIt;
 }