refactor: unuse state of the list

noriaki · Jun 24, 2020 · e930b2d · e930b2d
1 parent ef27308
commit e930b2d
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Showing 2 changed files with 22 additions and 6 deletions.
diff --git a/__tests__/hooks/useLinkedList.test.ts b/__tests__/hooks/useLinkedList.test.ts
@@ -5,8 +5,8 @@ import useLinkedList from '~/hooks/useLinkedList';
 describe('useLinkedList hooks', () => {
   it('set initial list', () => {
     const { result } = renderHook(() => useLinkedList<number>([1, 10, 100]));
-    const { state, index, value } = result.current;
-    expect(state).toEqual([1, 10, 100]);
+    const { list, index, value } = result.current;
+    expect(list).toEqual([1, 10, 100]);
     expect(index).toBe(0);
     expect(value).toBe(1);
   });
@@ -128,4 +128,21 @@ describe('useLinkedList hooks', () => {
     expect(result.current.index).toBe(list.length - 1);
     expect(result.current.value).toBe(100);
   });
+
+  it('multiple lists', () => {
+    const numbers = [1, 10, 100];
+    const strings = ['a', 'b', 'c'];
+
+    const { result: num } = renderHook(() => useLinkedList<number>(numbers));
+    const { result: str } = renderHook(() => useLinkedList<string>(strings));
+
+    expect(num.current.index).toBe(0);
+    expect(str.current.index).toBe(0);
+
+    act(() => {
+      num.current.next();
+    });
+    expect(num.current.index).toBe(1);
+    expect(str.current.index).toBe(0);
+  });
 });
diff --git a/src/hooks/useLinkedList.ts b/src/hooks/useLinkedList.ts
@@ -1,7 +1,7 @@
 import { useState, useCallback } from 'react';
 
 type LinkedListHook<T> = {
-  state: T[];
+  list: T[];
   index: number;
   value: T;
   next: () => void;
@@ -13,10 +13,9 @@ type LinkedListHook<T> = {
 };
 
 const useLinkedList = <T>(
-  initialLinkedList: T[] = [],
+  linkedList: T[] = [],
   initialIndex = 0,
 ): LinkedListHook<T> => {
-  const [linkedList] = useState(initialLinkedList);
   const [index, setIndex] = useState(initialIndex);
 
   const next = useCallback(
@@ -54,7 +53,7 @@ const useLinkedList = <T>(
   ]);
 
   return {
-    state: linkedList,
+    list: linkedList,
     index,
     value: linkedList[index],
     next,