blocks|key|2632848|text|将您的countTotalVotes函数移动到您的创建函数中：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2632849|var+createPolitician+=+function+(name)
{

++var+politician+=+{};+
++politician.name+=+name;
++//+set+to+an+empty+array+so+this+is+defined
++politician.electionResults+=+[];+
++politician.totalVotes+=+0;
++//+here+politician+exists,+add+a+function+to+the+object+that+you+can+call+later
++politician.countTotalVotes+=+function()+
++{
+++++this.totalVotes+=+0;
+++++for+(var+i+=+0;+i+<+this.electionResults.length;+i%2B%2B)
+++++{
++++++++this.totalVotes+=+this.totalVotes+%2B+this.electionResults[i];
++++++}
++}

++return+politician;

};|code-block|syntax|javascript|2632850|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

<p>Move your countTotalVotes function into your create function:</p>

<pre><code>var createPolitician = function (name)
{

  var politician = {}; 
  politician.name = name;
  // set to an empty array so this is defined
  politician.electionResults = []; 
  politician.totalVotes = 0;
  // here politician exists, add a function to the object that you can call later
  politician.countTotalVotes = function() 
  {
     this.totalVotes = 0;
     for (var i = 0; i &lt; this.electionResults.length; i++)
     {
        this.totalVotes = this.totalVotes + this.electionResults[i];
      }
  }

  return politician;

};
</code></pre>


blocks|key|2632893|text|错误消息应附带行号和列号。在本例中，错误发生在第32行：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2632894|politician.countTotalVotes+=+function()+|code-block|syntax|javascript|2632895|在createPolitician函数的定义中，您声明了一个名为politician的变量。var创建一个变量，该变量位于声明它的函数中。如果它不在函数内部，它会创建一个全局变量。|offset|length|style|CODE|2632896|您保留了声明变量的函数，因此它不再可用。|2632897|仔细想想，如果以后可以重用那个politician变量，那就很不明确了。它指的是什么？|2632898|如果您希望能够在政客上调用countTotalVotes()，那么Patrick关于使用类的评论是一个很好的方法。还可以将函数分配给从createPolitician返回的politician对象-这将为政治家的每个实例提供其自己的函数副本。|2632899|entityMap^0|0|0|1|G|W|A|1A|3|0|0|F|A|0|D|H|1V|G|2E|A|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|W|8|@$I|X|J|Y|K|L]|$I|Z|J|10|K|L]|$I|11|J|12|K|L]]|9|@]|A|$]]|$1|M|3|N|5|6|7|13|8|@]|9|@]|A|$]]|$1|O|3|P|5|6|7|14|8|@$I|15|J|16|K|L]]|9|@]|A|$]]|$1|Q|3|R|5|6|7|17|8|@$I|18|J|19|K|L]|$I|1A|J|1B|K|L]|$I|1C|J|1D|K|L]]|9|@]|A|$]]|$1|S|3|-4|5|6|7|1E|8|@]|9|@]|A|$]]]|T|$]]

<p>The error message should be accompanied with a line and column number. In this case, the error is occurring on line 32:</p>

<pre><code>politician.countTotalVotes = function() 
</code></pre>

<p>In the definition of the <code>createPolitician</code> function, you declared a variable named <code>politician</code>. <code>var</code> creates a variable that lives within the function it was declared in. If it is not inside of a function, it creates a global variable.</p>

<p>You left the function the variable was declared in, and thus it isn't usable anymore.</p>

<p>If you think about it, it'd be very ambiguous if you could re-use that <code>politician</code> variable later on. What would it refer to?</p>

<p>If you want to be able to call <code>countTotalVotes()</code> on the politicians, then Patrick's comment about using a Class is a good approach to take. You could also assign the function to the <code>politician</code> object that you return from <code>createPolitician</code> - this would give each instance of the politician its own copy of the function.</p>


blocks|key|2632963|text|+politician.countTotalVotes+=+...|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|2632964|这不会起作用，因为politician仅在您创建luke或oscar时存在(然后它会指向其中一个)。相反，您可以这样做：|unstyled|offset|length|style|CODE|2632965|luke.countTotalVotes+=+oscar.countTotalVotes+=+function()+{+/*...*+};|2632966|但对于更多的政客来说，这变得有点复杂。然而，你可以只做一个传递给政客的函数：|2632967|function+countTotalVotes(politician)+{
++//...
}

countTotalVotes(luke);|2632968|或者你使用继承的力量。|2632969|entityMap^0|0|9|A|O|4|T|5|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|V|8|@$G|W|H|X|I|J]|$G|Y|H|Z|I|J]|$G|10|H|11|I|J]]|9|@]|A|$]]|$1|K|3|L|5|6|7|12|8|@]|9|@]|A|$B|C]]|$1|M|3|N|5|F|7|13|8|@]|9|@]|A|$]]|$1|O|3|P|5|6|7|14|8|@]|9|@]|A|$B|C]]|$1|Q|3|R|5|F|7|15|8|@]|9|@]|A|$]]|$1|S|3|-4|5|F|7|16|8|@]|9|@]|A|$]]]|T|$]]

<pre><code> politician.countTotalVotes = ...
</code></pre>

<p>That won't work as <code>politician</code> only exists while you create <code>luke</code> or <code>oscar</code> (it then points to one of them). Instead you could do:</p>

<pre><code>luke.countTotalVotes = oscar.countTotalVotes = function() { /*...* };
</code></pre>

<p>But for more politicians that gets a bit complicated. You could however just make a function that you pass a politician into:</p>

<pre><code>function countTotalVotes(politician) {
  //...
}

countTotalVotes(luke);
</code></pre>

<p>Or you use the power of inheritance.</p>


blocks|key|2633084|text|正如我在评论中建议的那样，您可以将Politician重写为class，这基本上为您提供了一个可重用功能的模板。如果你不熟悉这个概念，一个好的谷歌术语应该是"prototypal+inheritance"，用来表示对这个主题的跟进。现在，这里使用class重写您的脚本|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2633085|​|2633086|class+Politician+{
++constructor+(name)+{
++++this.name+=+name;
++++this.electionResults+=+[];
++}

++//+no+need+to+even+write+a+.countTotalVotes()+method
++//+just+define+.totalVotes+as+a+getter+that+does+the+work
++get+totalVotes+()+{
++++var+total+=+0;

++++for+(var+i+=+0;+i+<+this.electionResults.length;+i%2B%2B)+{
++++++total+%2B=+this.electionResults[i];
++++}

++++return+total;
++}
}

var+oscar+=+new+Politician("Oscar+Jiminez");
var+luke+=+new+Politician("Luke+Spencer");

oscar.electionResults+=+[5,+1,+7,+2,+33,+6,+4,+2,+1,+14,+8,+3,+1,+11,+11,+0,+5,+3,+3,+3,+7,+4,+8,+9,+3,+7,+2,+2,+4,+2,+8,+3,+15,+15,+2,+12,+0,+4,+13,+1,+3,+2,+8,+21,+3,+2,+11,+1,+3,+7,+2];

luke.electionResults+=+[4,+2,+4,+4,+22,+3,+3,+1,+2,+15,+8,+1,+3,+9,+0,+6,+1,+5,+5,+1,+3,+7,+8,+1,+3,+3,+1,+3,+2,+2,+6,+2,+14,+0,+1,+6,+7,+3,+7,+3,+6,+1,+3,+17,+3,+1,+2,+11,+2,+3,+1];

oscar.electionResults[9]+=+1;
luke.electionResults[9]+=+28;

oscar.electionResults[4]+=+17;
luke.electionResults[4]+=+38;

oscar.electionResults[43]+=+11;
luke.electionResults[43]+=+27;

//+console.log(oscar.electionResults);
//+console.log(luke.electionResults);

//+these+are+no+longer+required
//+oscar.countTotalVotes();
//+luke.countTotalVotes();

console.log(oscar.name,+'has',+oscar.totalVotes,+'votes');
console.log(luke.name,+'has',+luke.totalVotes,+'votes');|code-block|syntax|javascript|2633087|2633088|entityMap|0|LINK|mutability|MUTABLE|url|https://developer.mozilla.org/en-US/docs/Learn/JavaScript/Objects/Object_prototypes|1|https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Classes^0|H|A|U|5|3F|5|26|O|0|3F|5|1|0|0|0|0^^$0|@$1|2|3|4|5|6|7|X|8|@$9|Y|A|Z|B|C]|$9|10|A|11|B|C]|$9|12|A|13|B|C]]|D|@$9|14|A|15|1|16]|$9|17|A|18|1|19]]|E|$]]|$1|F|3|G|5|6|7|1A|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|1B|8|@]|D|@]|E|$K|L]]|$1|M|3|G|5|6|7|1C|8|@]|D|@]|E|$]]|$1|N|3|-4|5|6|7|1D|8|@]|D|@]|E|$]]]|O|$P|$5|Q|R|S|E|$T|U]]|V|$5|Q|R|S|E|$T|W]]]]

<p>As I suggested in comments, you can rewrite <code>Politician</code> as a <code>class</code>, which basically gives you a template for reusable functionality. If you're not familiar with the concept, a good google term would be <a href="https://developer.mozilla.org/en-US/docs/Learn/JavaScript/Objects/Object_prototypes" rel="nofollow noreferrer">"prototypal inheritance"</a> for follow-up on the subject in general. For now, here's a rewrite of your script using a <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Classes" rel="nofollow noreferrer"><code>class</code></a>:</p>

<p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
<div class="snippet-code">
<pre class="snippet-code-js lang-js prettyprint-override"><code>class Politician {
  constructor (name) {
    this.name = name;
    this.electionResults = [];
  }

  // no need to even write a .countTotalVotes() method
  // just define .totalVotes as a getter that does the work
  get totalVotes () {
    var total = 0;

    for (var i = 0; i &lt; this.electionResults.length; i++) {
      total += this.electionResults[i];
    }

    return total;
  }
}

var oscar = new Politician("Oscar Jiminez");
var luke = new Politician("Luke Spencer");

oscar.electionResults = [5, 1, 7, 2, 33, 6, 4, 2, 1, 14, 8, 3, 1, 11, 11, 0, 5, 3, 3, 3, 7, 4, 8, 9, 3, 7, 2, 2, 4, 2, 8, 3, 15, 15, 2, 12, 0, 4, 13, 1, 3, 2, 8, 21, 3, 2, 11, 1, 3, 7, 2];

luke.electionResults = [4, 2, 4, 4, 22, 3, 3, 1, 2, 15, 8, 1, 3, 9, 0, 6, 1, 5, 5, 1, 3, 7, 8, 1, 3, 3, 1, 3, 2, 2, 6, 2, 14, 0, 1, 6, 7, 3, 7, 3, 6, 1, 3, 17, 3, 1, 2, 11, 2, 3, 1];

oscar.electionResults[9] = 1;
luke.electionResults[9] = 28;

oscar.electionResults[4] = 17;
luke.electionResults[4] = 38;

oscar.electionResults[43] = 11;
luke.electionResults[43] = 27;

// console.log(oscar.electionResults);
// console.log(luke.electionResults);

// these are no longer required
// oscar.countTotalVotes();
// luke.countTotalVotes();

console.log(oscar.name, 'has', oscar.totalVotes, 'votes');
console.log(luke.name, 'has', luke.totalVotes, 'votes');</code></pre>
</div>
</div>
</p>


blocks|key|2633114|text|我纠正了你代码中的错误。您可以更改代码，如下所示：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2633115|​|2633116|function+createPolitician(name)
{
++++var+politician+=+
++++{
++++++++name:+name,
++++++++electionResults:+null,
++++++++totalVotes:+0,

++++++++countTotalVotes:+function()+
++++++++{
++++++++++++//this.totalVotes+=+0;+<-+irrelevant+because+you+use+it+only+one+time
++++++++++++for(var+i+=+0;+i+<+this.electionResults.length;+i%2B%2B)//";"+symbol++on+the+end+is+your+mistake+too
++++++++++++{
++++++++++++++++this.totalVotes+%2B=+this.electionResults[i];
++++++++++++}

++++++++}
++++};
++++return+politician;
};

var+oscar+=+createPolitician("Oscar+Jiminez");
var+luke+=+createPolitician("Luke+Spencer");

oscar.electionResults+=+[5,+1,+7,+2,+33,+6,+4,+2,+1,+14,+8,+3,+1,+11,+11,+0,+5,+3,+3,+3,+7,+4,+8,+9,+3,+7,+2,+2,+4,+2,+8,+3,+15,+15,+2,+12,+0,+4,+13,+1,+3,+2,+8,+21,+3,+2,+11,+1,+3,+7,+2];

luke.electionResults+=+[4,+2,+4,+4,+22,+3,+3,+1,+2,+15,+8,+1,+3,+9,+0,+6,+1,+5,+5,+1,+3,+7,+8,+1,+3,+3,+1,+3,+2,+2,+6,+2,+14,+0,+1,+6,+7,+3,+7,+3,+6,+1,+3,+17,+3,+1,+2,+11,+2,+3,+1];

oscar.electionResults[9]+=+1;
luke.electionResults[9]+=+28;

oscar.electionResults[4]+=+17;
luke.electionResults[4]+=+38;

oscar.electionResults[43]+=+11;
luke.electionResults[43]+=+27;

console.log(oscar.electionResults);
console.log(luke.electionResults);

oscar.countTotalVotes();
luke.countTotalVotes();

console.log(oscar.name,+'has',+oscar.totalVotes,+'votes');
console.log(luke.name,+'has',+luke.totalVotes,+'votes');|code-block|syntax|javascript|2633117|2633118|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|M|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|N|8|@]|9|@]|A|$G|H]]|$1|I|3|C|5|6|7|O|8|@]|9|@]|A|$]]|$1|J|3|-4|5|6|7|P|8|@]|9|@]|A|$]]]|K|$]]

<p>I corrected your mistakes in your code. You could change your code like follows:</p>

<p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
<div class="snippet-code">
<pre class="snippet-code-js lang-js prettyprint-override"><code>function createPolitician(name)
{
    var politician = 
    {
        name: name,
        electionResults: null,
        totalVotes: 0,

        countTotalVotes: function() 
        {
            //this.totalVotes = 0; &lt;- irrelevant because you use it only one time
            for(var i = 0; i &lt; this.electionResults.length; i++)//";" symbol  on the end is your mistake too
            {
                this.totalVotes += this.electionResults[i];
            }

        }
    };
    return politician;
};

var oscar = createPolitician("Oscar Jiminez");
var luke = createPolitician("Luke Spencer");

oscar.electionResults = [5, 1, 7, 2, 33, 6, 4, 2, 1, 14, 8, 3, 1, 11, 11, 0, 5, 3, 3, 3, 7, 4, 8, 9, 3, 7, 2, 2, 4, 2, 8, 3, 15, 15, 2, 12, 0, 4, 13, 1, 3, 2, 8, 21, 3, 2, 11, 1, 3, 7, 2];

luke.electionResults = [4, 2, 4, 4, 22, 3, 3, 1, 2, 15, 8, 1, 3, 9, 0, 6, 1, 5, 5, 1, 3, 7, 8, 1, 3, 3, 1, 3, 2, 2, 6, 2, 14, 0, 1, 6, 7, 3, 7, 3, 6, 1, 3, 17, 3, 1, 2, 11, 2, 3, 1];

oscar.electionResults[9] = 1;
luke.electionResults[9] = 28;

oscar.electionResults[4] = 17;
luke.electionResults[4] = 38;

oscar.electionResults[43] = 11;
luke.electionResults[43] = 27;

console.log(oscar.electionResults);
console.log(luke.electionResults);

oscar.countTotalVotes();
luke.countTotalVotes();

console.log(oscar.name, 'has', oscar.totalVotes, 'votes');
console.log(luke.name, 'has', luke.totalVotes, 'votes');</code></pre>
</div>
</div>
</p>


blocks|key|2422790|text|这都是关于variable+scope的。在createPolitician函数外部声明politician对象变量，以便您从该函数访问。它不能被超出它的作用域访问，这就是为什么你得到一个未定义的错误。|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|2422791|entityMap|0|LINK|mutability|MUTABLE|url|https://www.w3schools.com/js/js_scope.asp^0|L|J|5|E|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@$9|O|A|P|B|C]]|D|@$9|Q|A|R|1|S]]|E|$]]|$1|F|3|-4|5|6|7|T|8|@]|D|@]|E|$]]]|G|$H|$5|I|J|K|E|$L|M]]]]

<p>It's all about <a href="https://www.w3schools.com/js/js_scope.asp" rel="nofollow noreferrer">variable scope</a>. <strong><em>Declare the politician object variable outside of the createPolitician function</em></strong> for you to access out of the function. It cannot be accessed out of its scope that is why you get an undefined error.</p>


<p>I am working on a project for SkillCrush and am getting a "not defined" error, when I feel as though I've defined the variable at the top of the code. I 100% know I'm doing something wrong, but not sure what. Any suggestions?</p>

<pre><code>var createPolitician = function (name)
{
    var politician = {}; //is this not defined here?
    politician.name = name;
    politician.electionResults = null;
    politician.totalVotes = 0;

    return politician;
};

var oscar = createPolitician("Oscar Jiminez");
var luke = createPolitician("Luke Spencer");

oscar.electionResults = [5, 1, 7, 2, 33, 6, 4, 2, 1, 14, 8, 3, 1, 11, 11, 0, 5, 3, 3, 3, 7, 4, 8, 9, 3, 7, 2, 2, 4, 2, 8, 3, 15, 15, 2, 12, 0, 4, 13, 1, 3, 2, 8, 21, 3, 2, 11, 1, 3, 7, 2];

luke.electionResults = [4, 2, 4, 4, 22, 3, 3, 1, 2, 15, 8, 1, 3, 9, 0, 6, 1, 5, 5, 1, 3, 7, 8, 1, 3, 3, 1, 3, 2, 2, 6, 2, 14, 0, 1, 6, 7, 3, 7, 3, 6, 1, 3, 17, 3, 1, 2, 11, 2, 3, 1];

oscar.electionResults[9] = 1;
luke.electionResults[9] = 28;

oscar.electionResults[4] = 17;
luke.electionResults[4] = 38;

oscar.electionResults[43] = 11;
luke.electionResults[43] = 27;

console.log(oscar.electionResults);
console.log(luke.electionResults);

politician.countTotalVotes = function() 
{
    this.totalVotes = 0;

    for (var i = 0; i &lt; this.electionResults.length; i++);
    {
        this.totalVotes = this.totalVotes + this.electionResults[i];
    }
}

oscar.countTotalVotes();
luke.countTotalVotes();

console.log(oscar.totalVotes);
console.log(luke.totalVotes);
</code></pre>

<p><strong>Error:</strong></p>

<pre><code>"error"
    "ReferenceError: politician is not defined
    at reloyur.js:32:1"
</code></pre>


Getting a "not defined" error in my JavaScript code when I think it is defined

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我正在为SkillCrush的一个项目工作，当我感觉好像在代码的顶部定义了变量时，我得到了一个“未定义”的错误。我100%知道我做错了什么，但不确定是什么。有什么建议吗？var createPolitician = function (name){    var politician = {}; //is this n...

问在我认为已定义的JavaScript代码中得到一个“未定义”错误
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问在我认为已定义的JavaScript代码中得到一个“未定义”错误
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