使用useRef

.eslintcache

@@ -1 +1 @@
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src/App.tsx

@@ -13,7 +13,7 @@ interface IShowResult {
 const App: React.FC = () => {
   const [show, setShow] = useState(true);
   const position = useMousePosition();
-  const [data, loading] = useURLLoader("https://dog.ceo/api/breeds/image/random");
+  const [data, loading] = useURLLoader("https://dog.ceo/api/breeds/image/random",[show]);
   const dogResult = data as IShowResult;
   return (
     <div className="App">

src/components/LikeButton.tsx

@@ -1,19 +1,30 @@
-import React, { useState, useEffect } from 'react';
+import React, { useState, useEffect, useRef } from 'react';
 
 const LikeButton: React.FC = () => {
     //obj是存储容器，setObj是设置容器的函数名
     const [obj, setObj] = useState({ like: 0, on: true });
+    //使用useRef,在所有的render中数据都保持一直
+    const likeRef = useRef(0);
 
     //这个useeffect没渲染完都会执行
     useEffect(() => {
         console.log("like button effect")
         document.title = `点击了${obj.like}次`;
-    },[obj.like]); //第二个参数 [obj.like]， 表示只有obj.like发生变化，才会触发effect
+    }, [obj.like]); //第二个参数 [obj.like]， 表示只有obj.like发生变化，才会触发effect
+
+    function handleAlertClick() {
+        setTimeout(() => {
+            setTimeout(() => {
+                alert('you haved click ' + obj.like + ', you haved click ' + likeRef.current);
+            }, 3000)
+        });
+    }
     return (
         <div>
-            <button onClick={() => { setObj({ like: obj.like + 1, on: obj.on }) }}>
+            <button onClick={() => { setObj({ like: obj.like + 1, on: obj.on }); likeRef.current++ }}>
                 点赞：{obj.like}
             </button>
+            <button onClick={handleAlertClick}>alert</button>
         </div>
     )
 }

src/hooks/useURLLoader.tsx

@@ -11,7 +11,7 @@ const useURLLoader = (url: string, deps: any[] = []) => {
             setData(result.data);
             setLoading(false);
         });
-    }, []);
+    }, deps);
     return [data, loading];
 }