103 lines
2.2 KiB
Markdown
103 lines
2.2 KiB
Markdown
---
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id: 587d7b8d367417b2b2512b5b
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challengeType: 1
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forumTopicId: 301233
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title: 学习函数式编程
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---
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## Description
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<section id='description'>
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函数式编程是一种方案简单、功能独立、对作用域外没有任何副作用的编程范式。
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<code>INPUT -> PROCESS -> OUTPUT</code>
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函数式编程：
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1）功能独立——不依赖于程序的状态（比如可能发生变化的全局变量）；
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2）纯函数——同一个输入永远能得到同一个输出；
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3）有限的副作用——可以严格地限制函数外部对状态的更改。
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</section>
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## Instructions
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<section id='instructions'>
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freeCodeCamp 成员在 love tea 的故事。
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在代码编辑器中，已经为你定义好了<code>prepareTea</code>和<code>getTea</code>函数。调用<code>getTea</code>函数为团队准备 40 杯茶，并将它们存储在<code>tea4TeamFCC</code>变量里。
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</section>
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## Tests
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<section id='tests'>
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```yml
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tests:
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- text: <code>tea4TeamFCC</code>变量里应有 40 杯为团队准备的茶。
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testString: assert(tea4TeamFCC.length === 40);
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- text: <code>tea4TeamFCC</code>变量里应有 greenTea。
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testString: assert(tea4TeamFCC[0] === 'greenTea');
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```
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</section>
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## Challenge Seed
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<section id='challengeSeed'>
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<div id='js-seed'>
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```js
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/**
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* A long process to prepare tea.
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* @return {string} A cup of tea.
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**/
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const prepareTea = () => 'greenTea';
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/**
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* Get given number of cups of tea.
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* @param {number} numOfCups Number of required cups of tea.
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* @return {Array<string>} Given amount of tea cups.
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**/
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const getTea = (numOfCups) => {
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const teaCups = [];
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for(let cups = 1; cups <= numOfCups; cups += 1) {
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const teaCup = prepareTea();
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teaCups.push(teaCup);
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}
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return teaCups;
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};
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// Add your code below this line
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const tea4TeamFCC = null; // :(
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// Add your code above this line
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console.log(tea4TeamFCC);
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```
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</div>
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</section>
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## Solution
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<section id='solution'>
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```js
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// solution required
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const prepareTea = () => 'greenTea';
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const getTea = (numOfCups) => {
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const teaCups = [];
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for(let cups = 1; cups <= numOfCups; cups += 1) {
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const teaCup = prepareTea();
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teaCups.push(teaCup);
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}
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return teaCups;
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};
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const tea4TeamFCC = getTea(40);
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```
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</section>
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