--- id: 587d7b8d367417b2b2512b5b title: 學習函數式編程 challengeType: 1 forumTopicId: 301233 dashedName: learn-about-functional-programming --- # --description-- 函數式編程是一種方案簡單、功能獨立、對作用域外沒有任何副作用的編程範式:`INPUT -> PROCESS -> OUTPUT`。 函數式編程: 1)功能獨立——不依賴於程序的狀態(比如可能發生變化的全局變量); 2)純函數——同一個輸入永遠能得到同一個輸出; 3)有限的副作用——可以嚴格地限制函數外部對狀態的更改。 # --instructions-- freeCodeCamp 的成員們愛喝茶。 在代碼編輯器中,已經爲你定義好了`prepareTea`和`getTea`函數。 調用 `getTea` 函數爲團隊準備 40 杯茶,並將它們存儲在 `tea4TeamFCC` 變量裏。 # --hints-- `tea4TeamFCC` 變量裏應有 40 杯爲團隊準備的茶。 ```js assert(tea4TeamFCC.length === 40); ``` `tea4TeamFCC` 變量裏應有幾杯 greenTea(綠茶)。 ```js assert(tea4TeamFCC[0] === 'greenTea'); ``` # --seed-- ## --seed-contents-- ```js // Function that returns a string representing a cup of green tea const prepareTea = () => 'greenTea'; /* Given a function (representing the tea type) and number of cups needed, the following function returns an array of strings (each representing a cup of a specific type of tea). */ const getTea = (numOfCups) => { const teaCups = []; for(let cups = 1; cups <= numOfCups; cups += 1) { const teaCup = prepareTea(); teaCups.push(teaCup); } return teaCups; }; // Only change code below this line const tea4TeamFCC = null; // Only change code above this line ``` # --solutions-- ```js const prepareTea = () => 'greenTea'; const getTea = (numOfCups) => { const teaCups = []; for(let cups = 1; cups <= numOfCups; cups += 1) { const teaCup = prepareTea(); teaCups.push(teaCup); } return teaCups; }; const tea4TeamFCC = getTea(40); ```