blocks|key|4513088|text|定义一个数组，然后按索引获取。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4513089|var+months+=+['January',+'February',+...];

var+month+=+months[mm+-+1]+%7C%7C+'';|code-block|syntax|javascript|4513090|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|$]]

Define an array, then get by index.

<pre><code>var months = ['January', 'February', ...];

var month = months[mm - 1] || '';
</code></pre>

blocks|key|4513126|text|如果根本不使用array呢:)|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4513127|var+objDate+=+new+Date("10/11/2009"),
++++locale+=+"en-us",
++++month+=+objDate.toLocaleString(locale,+{+month:+"long"+});

console.log(month);

//+or+if+you+want+the+shorter+date:+(also+possible+to+use+"narrow"+for+"O"
console.log(objDate.toLocaleString(locale,+{+month:+"short"+}));|code-block|syntax|javascript|4513128|根据David+Storey的回答，Get+month+name+from+Date|offset|length|4513129|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/questions/1643320/get-month-name-from-date^0|0|0|I|O|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@]|9|@$I|V|J|W|1|X]]|A|$]]|$1|K|3|-4|5|6|7|Y|8|@]|9|@]|A|$]]]|L|$M|$5|N|O|P|A|$Q|R]]]]

what about not to use array at all :)

<pre><code>var objDate = new Date("10/11/2009"),
 locale = "en-us",
 month = objDate.toLocaleString(locale, { month: "long" });

console.log(month);

// or if you want the shorter date: (also possible to use "narrow" for "O"
console.log(objDate.toLocaleString(locale, { month: "short" }));
</code></pre>

as per this answer <a href="https://stackoverflow.com/questions/1643320/get-month-name-from-date">Get month name from Date</a> from David Storey

blocks|key|5480|text|试试这个：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5481|var+months+=+{'1':+'January',+'2':+'February'};+//etc
var+month+=+months[mm];|code-block|syntax|javascript|5482|请注意，mm可以是整数或字符串，但它仍然有效。|offset|length|style|CODE|5483|如果您希望不存在的键产生空字符串''+(而不是undefined)，则添加以下行：|5484|month+=+(month+==+undefined)+?+''+:+month;|5485|JSFiddle。|5486|entityMap|0|LINK|mutability|MUTABLE|url|http://jsfiddle.net/s4d4rhf2/1/^0|0|0|4|2|0|G|2|N|9|0|0|0|8|0|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|11|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|12|8|@$I|13|J|14|K|L]]|9|@]|A|$]]|$1|M|3|N|5|6|7|15|8|@$I|16|J|17|K|L]|$I|18|J|19|K|L]]|9|@]|A|$]]|$1|O|3|P|5|D|7|1A|8|@]|9|@]|A|$E|F]]|$1|Q|3|R|5|6|7|1B|8|@]|9|@$I|1C|J|1D|1|1E]]|A|$]]|$1|S|3|-4|5|6|7|1F|8|@]|9|@]|A|$]]]|T|$U|$5|V|W|X|A|$Y|Z]]]]

Try this:

<pre><code>var months = {'1': 'January', '2': 'February'}; //etc
var month = months[mm];
</code></pre>

Note that <code>mm</code> can be an integer or a string and it will still work.

If you want non-existing keys to result in empty string <code>''</code> (instead of <code>undefined</code>), then add this line:

<pre><code>month = (month == undefined) ? '' : month;
</code></pre>

<a href="http://jsfiddle.net/s4d4rhf2/1/">JSFiddle</a>.

blocks|key|5517|text|您可以创建一个数组，然后查找月份名称：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5518|var+months+=+['January','February','March','April','May','June','July','August','September','October','November','December']


var+month+=+months[mm-1]+%7C%7C+'';|code-block|syntax|javascript|5519|查看@CupawnTae给出的答案，了解代码%7C%7C+''背后的rational|offset|length|style|CODE|5520|entityMap^0|0|0|M|5|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@$I|R|J|S|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

You could create an array instead and lookup the month name:

<pre><code>var months = ['January','February','March','April','May','June','July','August','September','October','November','December']


var month = months[mm-1] || '';
</code></pre>

See the answer by @CupawnTae for the rational behind the code <code>|| ''</code>

blocks|key|4513103|text|您可以使用数组来完成此操作：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4513104|var+months+=+['January',+'February',+'March',+'April',+
++++++++++++++'May',+'June',+'July',+'August',+
++++++++++++++'September',+'October',+'November',+'December'];

var+month+=+months[mm+-+1]+%7C%7C+'';|code-block|syntax|javascript|4513105|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|$]]

You could do it using an array:

<pre><code>var months = ['January', 'February', 'March', 'April', 
 'May', 'June', 'July', 'August', 
 'September', 'October', 'November', 'December'];

var month = months[mm - 1] || '';
</code></pre>

blocks|key|4513165|text|下面是另一个选项，它只使用一个变量，并且在mm超出范围时仍然应用默认值''。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|4513166|var+month+=+['January',+'February',+'March',
+++++++++++++'April',+'May',+'June',+'July',
+++++++++++++'August',+'September',+'October',
+++++++++++++'November',+'December'
++++++++++++][mm-1]+%7C%7C+'';|code-block|syntax|javascript|4513167|entityMap^0|L|2|Z|2|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]|$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|S|8|@]|D|@]|E|$]]]|L|$]]

Here's another option that uses only 1 variable and still applies the default value <code>''</code> when <code>mm</code> is outside of range.

<pre class="lang-js prettyprint-override"><code>var month = ['January', 'February', 'March',
 'April', 'May', 'June', 'July',
 'August', 'September', 'October',
 'November', 'December'
 ][mm-1] || '';
</code></pre>

blocks|key|4513209|text|您可以使用条件运算符将其编写为表达式，而不是开关：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4513210|var+month+=
++mm+==+1+?+'January'+:
++mm+==+2+?+'February'+:
++mm+==+3+?+'March'+:
++mm+==+4+?+'April'+:
++mm+==+5+?+'May'+:
++mm+==+6+?+'June'+:
++mm+==+7+?+'July'+:
++mm+==+8+?+'August'+:
++mm+==+9+?+'September'+:
++mm+==+10+?+'October'+:
++mm+==+11+?+'November'+:
++mm+==+12+?+'December'+:
++'';|code-block|syntax|javascript|4513211|如果你以前没有见过链式条件运算符，那么这篇文章一开始可能很难读懂。将其编写为表达式使得一个方面比原始代码更容易看到；很明显，代码的目的是为变量month赋值。|offset|length|style|CODE|4513212|entityMap^0|0|0|1Z|5|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@$I|R|J|S|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

You could write it as an expression instead of a switch, using conditional operators:

<pre><code>var month =
 mm == 1 ? 'January' :
 mm == 2 ? 'February' :
 mm == 3 ? 'March' :
 mm == 4 ? 'April' :
 mm == 5 ? 'May' :
 mm == 6 ? 'June' :
 mm == 7 ? 'July' :
 mm == 8 ? 'August' :
 mm == 9 ? 'September' :
 mm == 10 ? 'October' :
 mm == 11 ? 'November' :
 mm == 12 ? 'December' :
 '';
</code></pre>

If you haven't seen chained conditional operators before this may seem harder to read at first. Writing it as an expression makes one aspect even easier to see than the original code; it's clear that the intention of the code is to assign a value to the variable <code>month</code>.

blocks|key|5771|text|在前面的Cupawn+Tae's答案的基础上，我将其缩短为：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|5772|var+months+=+['January',+'February',+...];
var+month+=+(mm+>=+1+&&+mm+<=+12)+?+months[mm+-+1]+:+'';|code-block|syntax|javascript|5773|或者，是的，我很欣赏，可读性较差：|5774|var+month+=+months[mm+-+1]+%7C%7C+'';+//+as+mentioned+further+up|5775|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/a/29844172/4845042^0|4|C|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@$A|V|B|W|1|X]]|C|$]]|$1|D|3|E|5|F|7|Y|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|Z|8|@]|9|@]|C|$]]|$1|K|3|L|5|F|7|10|8|@]|9|@]|C|$G|H]]|$1|M|3|-4|5|6|7|11|8|@]|9|@]|C|$]]]|N|$O|$5|P|Q|R|C|$S|T]]]]

Building on <a href="https://stackoverflow.com/a/29844172/4845042">Cupawn Tae's</a> answer previous I'd shorten it to :

<pre><code>var months = ['January', 'February', ...];
var month = (mm &gt;= 1 &amp;&amp; mm &lt;= 12) ? months[mm - 1] : '';
</code></pre>

Alternatively, yes, I appreciate, less readable:

<pre><code>var month = months[mm - 1] || ''; // as mentioned further up
</code></pre>

blocks|key|4513225|text|var+getMonth=function(month){
+++//Return+string+to+number.
++++var+strMonth+=+['January',+'February',+'March',
+++++++++++++'April',+'May',+'June',+'July',
+++++++++++++'August',+'September',+'October',
+++++++++++++'November',+'December'
++++++++++++];
++++//return+number+to+string.
++++var+intMonth={'January':1,+'February':2,+'March':3,
+++++++++++++'April':4,+'May':5,+'June':6,+'July':7,
+++++++++++++'August':8,+'September':9,+'October':10,
+++++++++++++'November':11,+'December':12
++++++++++++};
++++//Check+type+and+return+
++++return+(typeof+month+===+"number")?strMonth[month-1]:intMonth[month]
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|4513226|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>var getMonth=function(month){
 //Return string to number.
 var strMonth = ['January', 'February', 'March',
 'April', 'May', 'June', 'July',
 'August', 'September', 'October',
 'November', 'December'
 ];
 //return number to string.
 var intMonth={'January':1, 'February':2, 'March':3,
 'April':4, 'May':5, 'June':6, 'July':7,
 'August':8, 'September':9, 'October':10,
 'November':11, 'December':12
 };
 //Check type and return 
 return (typeof month === "number")?strMonth[month-1]:intMonth[month]
}
</code></pre>

Is there a way to write this on fewer lines, but still easily readable?

<pre><code>var month = '';

switch(mm) {
 case '1':
 month = 'January';
 break;
 case '2':
 month = 'February';
 break;
 case '3':
 month = 'March';
 break;
 case '4':
 month = 'April';
 break;
 case '5':
 month = 'May';
 break;
 case '6':
 month = 'June';
 break;
 case '7':
 month = 'July';
 break;
 case '8':
 month = 'August';
 break;
 case '9':
 month = 'September';
 break;
 case '10':
 month = 'October';
 break;
 case '11':
 month = 'November';
 break;
 case '12':
 month = 'December';
 break;
}
</code></pre>

How to shorten switch case block converting a number to a month name?

有没有一种方法可以用更少的代码行来写这篇文章，但仍然很容易读懂？var month = '';switch(mm) {    case '1':        month = 'January';        break;    case '2':        month = 'February';        break;    case '3':        month = 'Marc

问如何将数字转换为月份名称？
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