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#2 useMemo #17

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Merged
huiji0315 merged 2 commits into from
May 27, 2021
Merged

#2 useMemo #17

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#2 useMemo
huiji0315 May 27, 2021
c30cbff
Merge branch '2-huiji' of https://github.com/huiji0315/react-study
huiji0315 May 27, 2021
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9 changes: 8 additions & 1 deletion 2주차리액트/장희지/begin-react/src/App.js
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Original file line number Diff line number Diff line change
@@ -1,7 +1,12 @@
import React, { useRef, useState } from 'react';
import React, { useRef, useState, useMemo } from 'react';
import UserList from './UserList';
import CreateUser from './CreateUser';

function countActiveUsers(users) {
console.log('활성 사용자 수를 세는중...');
return users.filter(user => user.active).length;
}

function App() {
const [inputs, setInputs] = useState({
username: '',
Expand Down Expand Up @@ -64,6 +69,7 @@ function App() {
)
);
};
const count = useMemo(() => countActiveUsers(users), [users]);
return (
<>
<CreateUser
Expand All @@ -73,6 +79,7 @@ function App() {
onCreate={onCreate}
/>
<UserList users={users} onRemove={onRemove} onToggle={onToggle} />
<div>활성사용자 수 : {count}</div>
</>
);
}
Expand Down