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Oliver Eyton-Williams ee1e8abd87 feat(curriculum): restore seed + solution to Chinese (#40683 )

* feat(tools): add seed/solution restore script

* chore(curriculum): remove empty sections' markers

* chore(curriculum): add seed + solution to Chinese

* chore: remove old formatter

* fix: update getChallenges

parse translated challenges separately, without reference to the source

* chore(curriculum): add dashedName to English

* chore(curriculum): add dashedName to Chinese

* refactor: remove unused challenge property 'name'

* fix: relax dashedName requirement

* fix: stray tag

Remove stray `pre` tag from challenge file.

Signed-off-by: nhcarrigan <nhcarrigan@gmail.com>

Co-authored-by: nhcarrigan <nhcarrigan@gmail.com>

2021-01-12 19:31:00 -07:00

3.2 KiB

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id, title, challengeType, forumTopicId, dashedName

id	title	challengeType	forumTopicId	dashedName
5a24c314108439a4d4036157	用 Redux 写一个计数器	6	301453	write-a-counter-with-redux

--description--

现在你已经了解了 Redux 的所有核心原则！你已经了解了如何创建 action 和 action creator，创建 Redux store，通过 store dispatch action，以及使用纯粹的 reducer 设计状态更新。你甚至已经看到过如何使用 reducer 组合管理复杂状态并处理异步操作。这些例子很简单，但这些概念是 Redux 的核心原则。如果你理解它们，你就可以开始构建自己的 Redux 应用了。接下来的挑战包括关于state不变性的一些细节，但是，这里是对你到目前为止学到的所有内容的回顾。

--instructions--

在本课程中，你将从头开始使用 Redux 实现一个简单的计数器。基本知识在代码编辑器中提供，但你必须完成详细的内容！使用提供给你的名称并定义incAction和decActio action creator counterReducer()，INCREMENT和DECREMENT action 类型，最后是 Redux store。一旦完成，你应该能够 dispatch INCREMENT或DECREMENT动作来增加或减少store中保存的状态。开始构建你的第一个 Redux 应用程序吧，祝你好运！

--hints--

action creator incAction应返回一个 action 对象 {type:"INCREMENT"}。

assert(incAction().type === INCREMENT);

action creator decAction应返回一个 action 对象 {type:"DECREMENT"}。

assert(decAction().type === DECREMENT);

Redux store 应该将state初始化为 0。

assert(store.getState() === 0);

在 Redux store 上 dispatch incAction应该将state增加 1。

assert(
  (function () {
    const initialState = store.getState();
    store.dispatch(incAction());
    const incState = store.getState();
    return initialState + 1 === incState;
  })()
);

在 Redux store 上 dispatch decAction应该将state减少 1。

assert(
  (function () {
    const initialState = store.getState();
    store.dispatch(decAction());
    const decState = store.getState();
    return initialState - 1 === decState;
  })()
);

counterReducer必须是一个函数。

assert(typeof counterReducer === 'function');

--seed--

--seed-contents--

const INCREMENT = null; // Define a constant for increment action types
const DECREMENT = null; // Define a constant for decrement action types

const counterReducer = null; // Define the counter reducer which will increment or decrement the state based on the action it receives

const incAction = null; // Define an action creator for incrementing

const decAction = null; // Define an action creator for decrementing

const store = null; // Define the Redux store here, passing in your reducers

--solutions--

const INCREMENT = 'INCREMENT';
const DECREMENT = 'DECREMENT';

const counterReducer = (state = 0, action) => {
  switch(action.type) {
    case INCREMENT:
      return state + 1;
    case DECREMENT:
      return state - 1;
    default:
      return state;
  }
};

const incAction = () => {
  return {
    type: INCREMENT
  }
};

const decAction = () => {
  return {
    type: DECREMENT
  }
};

const store = Redux.createStore(counterReducer);

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