Add missing nulls in the type declaration (#45)

* Add missing nulls in the type declaration

* Remove useless tests/types.ts & add --strict for tsc

package.json

@@ -20,7 +20,7 @@
     "prebuild": "npm run lint",
     "lint": "eslint src",
     "build": "rollup -c && npm run types",
-    "types": "tsc src/index.d.ts tests/types.ts",
+    "types": "tsc --strict src/index.d.ts",
     "prebenchmark": "npm run build",
     "benchmark": "node bench/benchmark.js",
     "start": "npm run test:watch",

src/index.d.ts

@@ -15,23 +15,23 @@ export default class AVLTree<Key extends any, Value extends any> {
   size: number;
   insert(key: Key, data?: Value): Node<Key, Value>;
   remove(key: Key): Node<Key, Value>;
-  find(key: Key): Node<Key, Value>;
-  at(index: number): Node<Key, Value>;
+  find(key: Key): Node<Key, Value> | null;
+  at(index: number): Node<Key, Value> | null;
   contains(key: Key): boolean;
   isEmpty(): boolean;
   keys(): Array<Key>;
   values(): Array<Value>;
-  pop(): Node<Key, Value>;
-  popMax(): Node<Key, Value>;
-  min(): Key;
-  max(): Key;
-  minNode(): Node<Key, Value>;
-  maxNode(): Node<Key, Value>;
+  pop(): Node<Key, Value> | null;
+  popMax(): Node<Key, Value> | null;
+  min(): Key | null;
+  max(): Key | null;
+  minNode(): Node<Key, Value> | null;
+  maxNode(): Node<Key, Value> | null;
   forEach(callback: ForEachCallback<Key, Value>): AVLTree<Key, Value>;
   range(minKey: Key, maxKey: Key, visit: TraverseCallback<Key, Value>, context?: any): AVLTree<Key, Value>;
   load(keys: Array<Key>, values?: Array<Value>, presort?: boolean): AVLTree<Key, Value>;
-  prev(node: Node<Key, Value>): Node<Key, Value>;
-  next(node: Node<Key, Value>): Node<Key, Value>;
+  prev(node: Node<Key, Value>): Node<Key, Value> | null;
+  next(node: Node<Key, Value>): Node<Key, Value> | null;
   isBalanced(): boolean;
   toString(): string;
   destroy(): AVLTree<Key, Value>;