Implement Collection

src/collection/mapNotNull.ts

@@ -0,0 +1,8 @@
+export function mapNotNull<T, R>(value: T[], transform: (it: T) => R | null): R[] {
+    const result: R[] = [];
+    for (const it of value) {
+        const transformed = transform(it);
+        if (transformed !== null) result.push(transformed);
+    }
+    return result;
+}