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freeCodeCamp/curriculum/challenges/chinese-traditional/03-front-end-development-libraries/redux/use-a-switch-statement-to-handle-multiple-actions.md
Shaun Hamilton c2a11ad00d feat: add 'back/front end' in curriculum (#42596)
* chore: rename APIs and Microservices to include "Backend" (#42515)

* fix typo

* fix typo

* undo change

* Corrected grammar mistake

Corrected a grammar mistake by removing a comma.

* change APIs and Microservices cert title

* update title

* Change APIs and Microservices certi title

* Update translations.json

* update title

* feat(curriculum): rename apis and microservices cert

* rename folder structure

* rename certificate

* rename learn Markdown

* apis-and-microservices -> back-end-development-and-apis

* update backend meta

* update i18n langs and cypress test

Co-authored-by: Shaun Hamilton <shauhami020@gmail.com>

* fix: add development to front-end libraries (#42512)

* fix: added-the-word-Development-to-front-end-libraries

* fix/added-the-word-Development-to-front-end-libraries

* fix/added-word-development-to-front-end-libraries-in-other-related-files

* fix/added-the-word-Development-to-front-end-and-all-related-files

* fix/removed-typos-from-last-commit-in-index.md

* fix/reverted-changes-that-i-made-to-dependecies

* fix/removed xvfg

* fix/reverted changes that i made to package.json

* remove unwanted changes

* front-end-development-libraries changes

* rename backend certSlug and README

* update i18n folder names and keys

* test: add legacy path redirect tests

This uses serve.json from the client-config repo, since we currently use
that in production

* fix: create public dir before moving serve.json

* fix: add missing script

* refactor: collect redirect tests

* test: convert to cy.location for stricter tests

* rename certificate folder to 00-certificates

* change crowdin config to recognise new certificates location

* allow translations to be used

Co-authored-by: Nicholas Carrigan (he/him) <nhcarrigan@gmail.com>

* add forwards slashes to path redirects

* fix cypress path tests again

* plese cypress

* fix: test different challenge

Okay so I literally have no idea why this one particular challenge
fails in Cypress Firefox ONLY. Tom and I paired and spun a full build
instance and confirmed in Firefox the page loads and redirects as
expected. Changing to another bootstrap challenge passes Cypress firefox
locally. Absolutely boggled by this.

AAAAAAAAAAAAAAA

* fix: separate the test

Okay apparently the test does not work unless we separate it into
a different `it` statement.

>:( >:( >:( >:(

Co-authored-by: Sujal Gupta <55016909+heysujal@users.noreply.github.com>
Co-authored-by: Noor Fakhry <65724923+NoorFakhry@users.noreply.github.com>
Co-authored-by: Oliver Eyton-Williams <ojeytonwilliams@gmail.com>
Co-authored-by: Nicholas Carrigan (he/him) <nhcarrigan@gmail.com>
2021-08-13 21:57:13 -05:00

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id, title, challengeType, forumTopicId, dashedName
id title challengeType forumTopicId dashedName
5a24c314108439a4d4036151 使用 Switch 語句處理多個 Actions 6 301449 use-a-switch-statement-to-handle-multiple-actions

--description--

可以定義 Redux store 處理多種 action 類型。 假設在 Redux store 中管理用戶身份驗證。 希望用狀態表示用戶登錄和註銷。 使用 state 的 authenticated 屬性表示它。 還需要使用 action creators 創建與用戶登錄和用戶註銷相對應的 action以及 action 對象本身。

--instructions--

代碼編輯器爲你創建了 store、actions、action creators。 通過編寫 reducer 函數來處理多個身份驗證操作。 可以在 reducer 裏通過使用 JavaScript 的 switch 來響應不同的 action 事件。 這是編寫 Redux reducers 的標準模式。 switch 語句應該切換 action.type 並返回適當的身份驗證狀態。

注意: 此時,不要擔心 state 的不變性,因爲在這個示例中它很小而且很簡單。 所以對於每個操作都可以返回一個新對象,比如 {authenticated: true}。 另外,不要忘記在 switch 語句中寫一個 default case返回當前的 state。 這是很重要的,因爲當程序有多個 reducer當每一個 action 被 dispatch 時它們都會運行,即使 action 與該 reducer 無關。 在這種情況下,你要確保返回當前的 state

--hints--

調用函數 loginUser 應該返回一個 type 屬性設置爲字符串 LOGIN 的對象。

assert(loginUser().type === 'LOGIN');

調用函數 logoutUser 應該返回一個 type 屬性設置爲字符串 LOGOUT 的對象。

assert(logoutUser().type === 'LOGOUT');

store 應該設置一個 authenticated 屬性設置爲 false 的初始化對象。

assert(store.getState().authenticated === false);

dispatch loginUser應該將 store 中的 state 的 authenticated 值更新爲 true

assert(
  (function () {
    const initialState = store.getState();
    store.dispatch(loginUser());
    const afterLogin = store.getState();
    return (
      initialState.authenticated === false && afterLogin.authenticated === true
    );
  })()
);

dispatch logoutUser 應該將 store 中的 state 的 authenticated 值更新爲 false

assert(
  (function () {
    store.dispatch(loginUser());
    const loggedIn = store.getState();
    store.dispatch(logoutUser());
    const afterLogout = store.getState();
    return (
      loggedIn.authenticated === true && afterLogout.authenticated === false
    );
  })()
);

authReducer 函數應該使用 switch 語句處理多個 action 類型。

(getUserInput) =>
  assert(
    getUserInput('index').toString().includes('switch') &&
      getUserInput('index').toString().includes('case') &&
      getUserInput('index').toString().includes('default')
  );

--seed--

--seed-contents--

const defaultState = {
  authenticated: false
};

const authReducer = (state = defaultState, action) => {
  // Change code below this line

  // Change code above this line
};

const store = Redux.createStore(authReducer);

const loginUser = () => {
  return {
    type: 'LOGIN'
  }
};

const logoutUser = () => {
  return {
    type: 'LOGOUT'
  }
};

--solutions--

const defaultState = {
  authenticated: false
};

const authReducer = (state = defaultState, action) => {

  switch (action.type) {

    case 'LOGIN':
      return {
        authenticated: true
      }

    case 'LOGOUT':
      return {
        authenticated: false
      }

    default:
      return state;

  }

};

const store = Redux.createStore(authReducer);

const loginUser = () => {
  return {
    type: 'LOGIN'
  }
};

const logoutUser = () => {
  return {
    type: 'LOGOUT'
  }
};