101 lines
2.2 KiB
Markdown
101 lines
2.2 KiB
Markdown
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---
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id: 56533eb9ac21ba0edf2244ab
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title: 瞭解變量名區分大小寫
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challengeType: 1
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videoUrl: 'https://scrimba.com/c/cd6GDcD'
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forumTopicId: 18334
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dashedName: understanding-case-sensitivity-in-variables
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---
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# --description--
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在 JavaScript 中所有的變量和函數名都是大小寫敏感的。 要區別對待大寫字母和小寫字母。
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`MYVAR` 與 `MyVar` 和 `myvar` 是不同的變量。 這有可能導致出現多個相似名字的的變量。 所以強烈地建議你,爲了保持代碼清晰*不要*使用這一特性。
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**最佳實踐**
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使用駝峯命名法(<dfn>camelCase</dfn>)來書寫一個 Javascript 變量。 在駝峯命名法(<dfn>camelCase</dfn>)中,變量名的第一個單詞的首寫字母小寫,後面的單詞的第一個字母大寫
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**示例:**
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```js
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var someVariable;
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var anotherVariableName;
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var thisVariableNameIsSoLong;
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```
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# --instructions--
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修改已聲明的變量,讓它們的命名符合駝峯命名法(<dfn>camelCase</dfn>)的規範。
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不要創建任何新變量。
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# --hints--
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`studlyCapVar` 應該被定義並且值爲 `10`。
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```js
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assert(typeof studlyCapVar !== 'undefined' && studlyCapVar === 10);
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```
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`properCamelCase` 應該被定義並且值爲字符串 `A String`。
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```js
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assert(
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typeof properCamelCase !== 'undefined' && properCamelCase === 'A String'
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);
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```
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`titleCaseOver` 應該被定義並且值爲 `9000`。
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```js
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assert(typeof titleCaseOver !== 'undefined' && titleCaseOver === 9000);
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```
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`studlyCapVar` 在聲明和賦值時都應該使用駝峯命名法。
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```js
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assert(code.match(/studlyCapVar/g).length === 2);
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```
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`properCamelCase` 在聲明和賦值時都應該使用駝峯命名法。
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```js
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assert(code.match(/properCamelCase/g).length === 2);
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```
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`titleCaseOver` 在聲明和賦值時都應該使用駝峯命名法。
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```js
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assert(code.match(/titleCaseOver/g).length === 2);
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```
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# --seed--
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## --seed-contents--
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```js
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// Variable declarations
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var StUdLyCapVaR;
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var properCamelCase;
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var TitleCaseOver;
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// Variable assignments
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STUDLYCAPVAR = 10;
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PRoperCAmelCAse = "A String";
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tITLEcASEoVER = 9000;
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```
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# --solutions--
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```js
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var studlyCapVar;
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var properCamelCase;
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var titleCaseOver;
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studlyCapVar = 10;
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properCamelCase = "A String";
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titleCaseOver = 9000;
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```
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