JavaScript 练习帮助设置和获取属性答案

【问题标题】：JavaScript exercise help setting and getting propertiesJavaScript 练习帮助设置和获取属性
【发布时间】：2018-05-15 01:10:18
【问题描述】：

我正在为学校做一些 JavaScript 练习，而数字 8 真的让我很难过。

这是原始的完整练习：

/*
 *  @function   {Object} Person
 *  @param      string name
 */
function Person(name) {
    // Todo: Complete the function

}


var Mike = Person('John Doe');
var Bob = Person('John Doe');
var Worker = Person('John Doe');

/*
 * Directions Part 1:
 *  - Update the Person function so the below statements don't generate any errors
 */
Mike.setName('Mike');   // name setter
Mike.getName();         // name getter


/*
 * Directions Part 2:
 *  - Update the Person function so the below statements don't generate any errors
 */
Bob.name('Bob');    // name setter
Bob.name();         // name getter


/*
 * Directions part 3:
 * - Update the Person function so the below statements don't generate any errors
 *
 */
Worker.setName('Kevin');            // name setter
Worker.profession('Programmer');    // profession setter
Worker.profession();                // profession getter

Worker.introduce();                 // Calling this method, the Person will introduce themselves with their name and profession.

我认为我的部分困惑是我不太明白它对我的要求。另一部分是我不熟悉这种编码风格，因为我通常不会有这样的浮动语句。

我想最终的结果应该是给出名字和职业，但我看不到以这种方式完成它的路径。

【问题讨论】：

Todo: Complete the function ...嗯...有吗？不要指望我们为你做功课：p
不，我不知道该怎么办。
How do I ask and answer homework questions?
Mike 未定义，如果我定义了它，那么 setName 不是函数。我不明白为什么要这样设置？
@JaromandaX - 想知道这是否足够。他们没有使用new Person() 创建对象。看来人需要返回一些东西。

标签： javascript object properties undefined-behavior

【解决方案1】：

是这样的：

//<![CDATA[
/* external.js */
var doc, bod, I, Person, old = onload; // for use on other loads
onload = function(){
if(old)old(); // change old var name if using technique on other pages
doc = document; bod = doc.body;
I = function(id){
  return doc.getElementById(id);
}
Person = function(last, first, middle, job){
  this.first = first; this.middle = middle; this.last = last; this.job = job;
  this.firstName = function(first){
    if(first === undefined){
      return this.first;
    }
    this.first = first;
    return this;
  }
  this.middleName = function(middle){
    if(middle === undefined){
      return this.middle;
    }
    this.middle = middle;
    return this;
  }
  this.lastName = function(last){
    if(last === undefined){
      return this.last;
    }
    this.last = last;
    return this;
  }
  this.profession = function(profession){
    if(profession === undefined){
      return this.job;
    }
    this.job = profession;
    return this;
  }
}
var out = I('out'), newbie = new Person;
newbie.firstName('Bob').lastName('Smith').profession('plummer');
out.innerHTML = newbie.lastName()+', '+newbie.firstName()+'; profession:'+newbie.profession();
/* you wouldn't need to use empty methods, with this design though
out.innerHTML = newbie.last+', '+newbie.first+'; profession:'+newbie.job;
would also work
*/

}
//]]>

/* external.css */
html,body{
  padding:0; margin:0;
}
body{
  background:#000; overflow-y:scroll;
}
.main{
  width:936px; background:#ccc; padding:20px; margin:0 auto;
}
#out{
  background:#fff; padding:10px;
}

<!DOCTYPE html>
<html xmlns='http://www.w3.org/1999/xhtml' xml:lang='en' lang='en'>
  <head>
    <meta http-equiv='content-type' content='text/html;charset=utf-8' />
    <meta name='viewport' content='width=device-width' />
    <title>test</title>
    <link type='text/css' rel='stylesheet' href='external.css' />
    <script type='text/javascript' src='external.js'></script>
  </head>
<body>
  <div class='main'>
    <div id='out'></div>
  </div>
</body>
</html>

【讨论】：