blocks|key|1477739|text|简单的一行代码：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1477740|[1,+false,+"",+undefined,+2].filter(Boolean);+//+[1,+2]|code-block|syntax|javascript|1477741|或者使用underscorejs.org|offset|length|1477742|_.filter([1,+false,+"",+undefined,+2],+Boolean);+//+[1,+2]
//+or+even:
_.compact([1,+false,+"",+undefined,+2]);+//+[1,+2]|1477743|entityMap|0|LINK|mutability|MUTABLE|url|http://underscorejs.org/#filter^0|0|0|4|G|0|0|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]]|$1|G|3|H|5|6|7|W|8|@]|9|@$I|X|J|Y|1|Z]]|A|$]]|$1|K|3|L|5|D|7|10|8|@]|9|@]|A|$E|F]]|$1|M|3|-4|5|6|7|11|8|@]|9|@]|A|$]]]|N|$O|$5|P|Q|R|A|$S|T]]]]

<p>Simply one liner:</p>

<pre><code>[1, false, "", undefined, 2].filter(Boolean); // [1, 2]
</code></pre>

<p>or using <a href="http://underscorejs.org/#filter">underscorejs.org</a>:</p>

<pre><code>_.filter([1, false, "", undefined, 2], Boolean); // [1, 2]
// or even:
_.compact([1, false, "", undefined, 2]); // [1, 2]
</code></pre>


blocks|key|1477376|text|如果你有Javascript1.6或更高版本，你可以通过一个简单的return+true回调函数来使用Array.filter，例如：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1477377|arr+=+arr.filter(function()+{+return+true;+});|code-block|syntax|javascript|1477378|因为.filter会自动跳过原始数组中缺少的元素。|1477379|上面链接的MDN页面还包含一个很好的filter错误检查版本，可以在不支持官方版本的JavaScript解释器中使用。|1477380|请注意，这不会删除null条目，也不会删除具有显式undefined值的条目，而是OP特别请求的“缺失”条目。|1477381|entityMap|0|LINK|mutability|MUTABLE|url|https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Objects/Array/filter^0|X|B|1F|C|1F|C|0|0|0|2|7|0|I|6|0|9|4|P|9|0^^$0|@$1|2|3|4|5|6|7|Y|8|@$9|Z|A|10|B|C]|$9|11|A|12|B|C]]|D|@$9|13|A|14|1|15]]|E|$]]|$1|F|3|G|5|H|7|16|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|17|8|@$9|18|A|19|B|C]]|D|@]|E|$]]|$1|M|3|N|5|6|7|1A|8|@$9|1B|A|1C|B|C]]|D|@]|E|$]]|$1|O|3|P|5|6|7|1D|8|@$9|1E|A|1F|B|C]|$9|1G|A|1H|B|C]]|D|@]|E|$]]|$1|Q|3|-4|5|6|7|1I|8|@]|D|@]|E|$]]]|R|$S|$5|T|U|V|E|$W|X]]]]

<p>If you've got Javascript 1.6 or later you can use <a href="https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Objects/Array/filter" rel="noreferrer"><code>Array.filter</code></a> using a trivial <code>return true</code> callback function, e.g.:</p>

<pre><code>arr = arr.filter(function() { return true; });
</code></pre>

<p>since <code>.filter</code> automatically skips missing elements in the original array.</p>

<p>The MDN page linked above also contains a nice error-checking version of <code>filter</code> that can be used in JavaScript interpreters that don't support the official version.</p>

<p>Note that this will not remove <code>null</code> entries nor entries with an explicit <code>undefined</code> value, but the OP specifically requested "missing" entries.</p>


blocks|key|1692771|text|干净利落的方法。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1692772|var+arr+=+[0,1,2,"Thomas","false",false,true,null,3,4,undefined,5,"end"];
arr+=+arr.filter(Boolean);
//+[1,+2,+"Thomas",+"false",+true,+3,+4,+5,+"end"]|code-block|syntax|javascript|1692773|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>The clean way to do it.</p>

<pre><code>var arr = [0,1,2,"Thomas","false",false,true,null,3,4,undefined,5,"end"];
arr = arr.filter(Boolean);
// [1, 2, "Thomas", "false", true, 3, 4, 5, "end"]
</code></pre>


blocks|key|1693628|text|简单的ES6|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1693629|['a','b','',,,'w','b'].filter(v+=>+v);|code-block|syntax|javascript|1693630|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>Simple ES6</p>

<pre><code>['a','b','',,,'w','b'].filter(v =&gt; v);
</code></pre>


blocks|key|1478387|text|ES6：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1478388|let+newArr+=+arr.filter(e+=>+e);|code-block|syntax|javascript|1478389|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|$]]

<h1>ES6:</h1>

<pre><code>let newArr = arr.filter(e =&gt; e);
</code></pre>


blocks|key|1477463|text|@Alnitak|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1477464|实际上，如果您添加一些额外的代码，Array.filter可以在所有浏览器上运行。见下文。|1477465|var+array+=+["","one",0,"",null,0,1,2,4,"two"];

function+isempty(x){
if(x!=="")
++++return+true;
}
var+res+=+array.filter(isempty);
document.writeln(res.toJSONString());
//+gives:+["one",0,null,0,1,2,4,"two"]++|code-block|syntax|javascript|1477466|这是你需要为IE添加的代码，但是过滤器和函数式编程是值得的。|1477467|//This+prototype+is+provided+by+the+Mozilla+foundation+and
//is+distributed+under+the+MIT+license.
//http://www.ibiblio.org/pub/Linux/LICENSES/mit.license

if+(!Array.prototype.filter)
{
++Array.prototype.filter+=+function(fun+/*,+thisp*/)
++{
++++var+len+=+this.length;
++++if+(typeof+fun+!=+"function")
++++++throw+new+TypeError();

++++var+res+=+new+Array();
++++var+thisp+=+arguments[1];
++++for+(var+i+=+0;+i+<+len;+i%2B%2B)
++++{
++++++if+(i+in+this)
++++++{
++++++++var+val+=+this[i];+//+in+case+fun+mutates+this
++++++++if+(fun.call(thisp,+val,+i,+this))
++++++++++res.push(val);
++++++}
++++}

++++return+res;
++};
}|1477468|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|P|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|Q|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|S|8|@]|9|@]|A|$G|H]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

<p>@Alnitak</p>

<p>Actually Array.filter works on all browsers if you add some extra code. See below.</p>

<pre><code>var array = ["","one",0,"",null,0,1,2,4,"two"];

function isempty(x){
if(x!=="")
    return true;
}
var res = array.filter(isempty);
document.writeln(res.toJSONString());
// gives: ["one",0,null,0,1,2,4,"two"]  
</code></pre>

<p>This is the code you need to add for IE, but filter and Functional programmingis worth is imo.</p>

<pre><code>//This prototype is provided by the Mozilla foundation and
//is distributed under the MIT license.
//http://www.ibiblio.org/pub/Linux/LICENSES/mit.license

if (!Array.prototype.filter)
{
  Array.prototype.filter = function(fun /*, thisp*/)
  {
    var len = this.length;
    if (typeof fun != "function")
      throw new TypeError();

    var res = new Array();
    var thisp = arguments[1];
    for (var i = 0; i &lt; len; i++)
    {
      if (i in this)
      {
        var val = this[i]; // in case fun mutates this
        if (fun.call(thisp, val, i, this))
          res.push(val);
      }
    }

    return res;
  };
}
</code></pre>


blocks|key|1693238|text|因为没有人提到它，而且大多数人都在他们的项目中包含了下划线，所以你也可以使用_.without(array,+*values);。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1693239|_.without(["text",+"string",+null,+null,+null,+"text"],+null)
//+=>+["text",+"string",+"text"]|code-block|syntax|javascript|1693240|entityMap^0|12|Q|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

<p>Since nobody else mentioned it and most people have underscore included in their project you can also use <code>_.without(array, *values);</code>. </p>

<pre><code>_.without(["text", "string", null, null, null, "text"], null)
// =&gt; ["text", "string", "text"]
</code></pre>


blocks|key|1692434|text|您可能会发现，循环遍历数组并从数组中希望保留的项中构建一个新数组比尝试循环和拼接要容易得多，因为在循环数组时修改数组的长度可能会带来问题。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1692435|你可以这样做：|1692436|function+removeFalsyElementsFromArray(someArray)+{
++++var+newArray+=+[];
++++for(var+index+=+0;+index+<+someArray.length;+index%2B%2B)+{
++++++++if(someArray[index])+{
++++++++++++newArray.push(someArray[index]);
++++++++}
++++}
++++return+newArray;
}|code-block|syntax|javascript|1692437|实际上，这里有一个更通用的解决方案：|1692438|function+removeElementsFromArray(someArray,+filter)+{
++++var+newArray+=+[];
++++for(var+index+=+0;+index+<+someArray.length;+index%2B%2B)+{
++++++++if(filter(someArray[index])+==+false)+{
++++++++++++newArray.push(someArray[index]);
++++++++}
++++}
++++return+newArray;
}

//+then+provide+one+or+more+filter+functions+that+will+
//+filter+out+the+elements+based+on+some+condition:
function+isNullOrUndefined(item)+{
++++return+(item+==+null+%7C%7C+typeof(item)+==+"undefined");
}

//+then+call+the+function+like+this:
var+myArray+=+[1,2,,3,,3,,,,,,4,,4,,5,,6,,,,];
var+results+=+removeElementsFromArray(myArray,+isNullOrUndefined);

//+results+==+[1,2,3,3,4,4,5,6]|1692439|你明白了--你可以有其他类型的过滤函数。可能比你需要的多，但我觉得很大方...;)|1692440|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|R|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|S|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|T|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|U|8|@]|9|@]|A|$G|H]]|$1|M|3|N|5|6|7|V|8|@]|9|@]|A|$]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

<p>You may find it easier to loop over your array and build a new array out of the items you want to keep from the array than by trying to loop and splice as has been suggested, since modifying the length of the array while it is being looped over can introduce problems.</p>

<p>You could do something like this:</p>

<pre><code>function removeFalsyElementsFromArray(someArray) {
    var newArray = [];
    for(var index = 0; index &lt; someArray.length; index++) {
        if(someArray[index]) {
            newArray.push(someArray[index]);
        }
    }
    return newArray;
}
</code></pre>

<p>Actually here is a more generic solution:</p>

<pre><code>function removeElementsFromArray(someArray, filter) {
    var newArray = [];
    for(var index = 0; index &lt; someArray.length; index++) {
        if(filter(someArray[index]) == false) {
            newArray.push(someArray[index]);
        }
    }
    return newArray;
}

// then provide one or more filter functions that will 
// filter out the elements based on some condition:
function isNullOrUndefined(item) {
    return (item == null || typeof(item) == "undefined");
}

// then call the function like this:
var myArray = [1,2,,3,,3,,,,,,4,,4,,5,,6,,,,];
var results = removeElementsFromArray(myArray, isNullOrUndefined);

// results == [1,2,3,3,4,4,5,6]
</code></pre>

<p>You get the idea - you could then have other types of filter functions. Probably more than you need, but I was feeling generous... ;)</p>


blocks|key|1693719|text|你应该使用filter来获得一个不带空元素的数组。ES6上的示例|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1693720|const+array+=+[1,+32,+2,+undefined,+3];
const+newArray+=+array.filter(arr+=>+arr);|code-block|syntax|javascript|1693721|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>You should use filter to get array without empty elements. Example on ES6 </p>

<pre><code>const array = [1, 32, 2, undefined, 3];
const newArray = array.filter(arr =&gt; arr);
</code></pre>


blocks|key|1694149|text|要从数组中删除未定义的元素，只需使用|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1694150|​|1694151|const+array+=+[
++{+name:+"tim",+age:+1+},
++undefined,
++{+name:+"ewrfer",+age:+22+},
++{+name:+"3tf5gh",+age:+56+},
++null,
++{+name:+"kygm",+age:+19+},
++undefined,
];
console.log(array.filter(Boolean));|code-block|syntax|javascript|1694152|1694153|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>To remove undefined elements from an array you can simply use</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>const array = [
  { name: "tim", age: 1 },
  undefined,
  { name: "ewrfer", age: 22 },
  { name: "3tf5gh", age: 56 },
  null,
  { name: "kygm", age: 19 },
  undefined,
];
console.log(array.filter(Boolean));</code></pre>
</div>
</div>
</p>


blocks|key|1478649|text|删除所有空元素|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1478650|如果一个数组包含空对象、数组和字符串以及其他空元素，我们可以使用以下命令删除它们：|1478651|​|1478652|const+arr+=+[+[],+['not',+'empty'],+{},+{+key:+'value'+},+0,+1,+null,+2,+"",+"here",+"+",+3,+undefined,+3,+,+,+,+,+,+4,+,+4,+,+5,+,+6,+,+,+]

let+filtered+=+JSON.stringify(
++arr.filter((obj)+=>+{
++++return+![null,+undefined,+''].includes(obj)
++}).filter((el)+=>+{
++++return+typeof+el+!=+"object"+%7C%7C+Object.keys(el).length+>+0
++})
)

console.log(JSON.parse(filtered))|code-block|syntax|javascript|1478653|1478654|简单压缩(从数组中删除空元素)|1478655|使用ES6：|1478656|1478657|const+arr+=+[0,+1,+null,+2,+"",+3,+undefined,+3,+,+,+,+,+,+4,+,+4,+,+5,+,+6,+,+,+,]

let+filtered+=+arr.filter((obj)+=>+{+return+![null,+undefined].includes(obj)+})

console.log(filtered)|1478658|1478659|使用普通的Javascript+->|1478660|1478661|var+arr+=+[0,+1,+null,+2,+"",+3,+undefined,+3,+,+,+,+,+,+4,+,+4,+,+5,+,+6,+,+,+,]

var+filtered+=+arr.filter(function+(obj)+{+return+![null,+undefined].includes(obj)+})

console.log(filtered)|1478662|1478663|entityMap^0|0|0|0|0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|11|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|12|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|13|8|@]|9|@]|A|$]]|$1|F|3|G|5|H|7|14|8|@]|9|@]|A|$I|J]]|$1|K|3|E|5|6|7|15|8|@]|9|@]|A|$]]|$1|L|3|M|5|6|7|16|8|@]|9|@]|A|$]]|$1|N|3|O|5|6|7|17|8|@]|9|@]|A|$]]|$1|P|3|E|5|6|7|18|8|@]|9|@]|A|$]]|$1|Q|3|R|5|H|7|19|8|@]|9|@]|A|$I|J]]|$1|S|3|E|5|6|7|1A|8|@]|9|@]|A|$]]|$1|T|3|U|5|6|7|1B|8|@]|9|@]|A|$]]|$1|V|3|E|5|6|7|1C|8|@]|9|@]|A|$]]|$1|W|3|X|5|H|7|1D|8|@]|9|@]|A|$I|J]]|$1|Y|3|E|5|6|7|1E|8|@]|9|@]|A|$]]|$1|Z|3|-4|5|6|7|1F|8|@]|9|@]|A|$]]]|10|$]]

<h2>Removing all empty elements</h2>

<p>If an array contains empty Objects, Arrays, and Strings alongside other empty elements, we can remove them with:</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>const arr = [ [], ['not', 'empty'], {}, { key: 'value' }, 0, 1, null, 2, "", "here", " ", 3, undefined, 3, , , , , , 4, , 4, , 5, , 6, , , ]

let filtered = JSON.stringify(
  arr.filter((obj) =&gt; {
    return ![null, undefined, ''].includes(obj)
  }).filter((el) =&gt; {
    return typeof el != "object" || Object.keys(el).length &gt; 0
  })
)

console.log(JSON.parse(filtered))</code></pre>
</div>
</div>
</p>

<h2>Simple compacting (removing empty elements from an array)</h2>

<p>With ES6:</p>

<p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="true">
<div class="snippet-code">
<pre class="snippet-code-js lang-js prettyprint-override"><code>const arr = [0, 1, null, 2, "", 3, undefined, 3, , , , , , 4, , 4, , 5, , 6, , , ,]

let filtered = arr.filter((obj) =&gt; { return ![null, undefined].includes(obj) })

console.log(filtered)</code></pre>
</div>
</div>
</p>

<p>With plain Javascript -></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>var arr = [0, 1, null, 2, "", 3, undefined, 3, , , , , , 4, , 4, , 5, , 6, , , ,]

var filtered = arr.filter(function (obj) { return ![null, undefined].includes(obj) })

console.log(filtered)</code></pre>
</div>
</div>
</p>


blocks|key|1694067|text|可以将筛选器与索引和in运算符一起使用|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1694068|​|1694069|let+a+=+[1,,2,,,3];
let+b+=+a.filter((x,i)=>+i+in+a);

console.log({a,b});|code-block|syntax|javascript|1694070|1694071|entityMap^0|A|2|0|0|0|0^^$0|@$1|2|3|4|5|6|7|P|8|@$9|Q|A|R|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|S|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|T|8|@]|D|@]|E|$K|L]]|$1|M|3|G|5|6|7|U|8|@]|D|@]|E|$]]|$1|N|3|-4|5|6|7|V|8|@]|D|@]|E|$]]]|O|$]]

<p>You can use filter with index and <code>in</code> operator</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>let a = [1,,2,,,3];
let b = a.filter((x,i)=&gt; i in a);

console.log({a,b});</code></pre>
</div>
</div>
</p>


blocks|key|1692732|text|这又如何呢：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1692733|js>+[1,2,,3,,3,,,0,,,4,,4,,5,,6,,,,].filter(String).join(',')
1,2,3,3,0,4,4,5,6|code-block|syntax|javascript|1692734|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>What about that:</p>

<pre><code>js&gt; [1,2,,3,,3,,,0,,,4,,4,,5,,6,,,,].filter(String).join(',')
1,2,3,3,0,4,4,5,6
</code></pre>


blocks|key|1693084|text|另一种方法是利用数组的长度属性:将非空项打包到数组的“左边”，然后减少长度。这是一个-does不分配内存的就地算法，对于垃圾回收器来说太糟糕了，而且它具有非常好的最佳/平均/最坏情况行为。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1693085|与这里的其他解决方案相比，这个解决方案在Chrome上快2到50倍，在Firefox上快5到50倍，正如你可能在这里看到的：http://jsperf.com/remove-null-items-from-array|offset|length|1693086|下面的代码将不可枚举的'removeNull‘方法添加到数组中，该方法返回用于菊花链的'this’：|1693087|var+removeNull+=+function()+{
++++var+nullCount+=+0+++++++++++;
++++var+length++++=+this.length+;
++++for+(var+i=0,+len=this.length;+i<len;+i%2B%2B)+{+if+(!this[i])+{nullCount%2B%2B}+}
++++//+no+item+is+null
++++if+(!nullCount)+{+return+this}
++++//+all+items+are+null
++++if+(nullCount+==+length)+{+this.length+=+0;+return+this+}
++++//+mix+of+null+//+non-null
++++var+idest=0,+isrc=length-1;
++++length+-=+nullCount+;++++++++++++++++
++++while+(true)+{
+++++++++//+find+a+non+null+(source)+slot+on+the+right
+++++++++while+(!this[isrc])++{+isrc--;+nullCount--;+}+
+++++++++if++++(!nullCount)+{+break+}+++++++//+break+if+found+all+null
+++++++++//+find+one+null+slot+on+the+left+(destination)
+++++++++while+(+this[idest])+{+idest%2B%2B++}++
+++++++++//+perform+copy
+++++++++this[idest]=this[isrc];
+++++++++if+(!(--nullCount))+{break}
+++++++++idest%2B%2B;++isrc+--;+
++++}
++++this.length=length;+
++++return+this;
};++

Object.defineProperty(Array.prototype,+'removeNull',+
++++++++++++++++{+value+:+removeNull,+writable+:+true,+configurable+:+true+}+)+;|code-block|syntax|javascript|1693088|entityMap|0|LINK|mutability|MUTABLE|url|http://jsperf.com/remove-null-items-from-array^0|0|1Q|1A|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|V|8|@]|9|@$D|W|E|X|1|Y]]|A|$]]|$1|F|3|G|5|6|7|Z|8|@]|9|@]|A|$]]|$1|H|3|I|5|J|7|10|8|@]|9|@]|A|$K|L]]|$1|M|3|-4|5|6|7|11|8|@]|9|@]|A|$]]]|N|$O|$5|P|Q|R|A|$S|T]]]]

<p>Another way to do it is to take advantage of the length property of the array : pack the non-null items on the 'left' of the array, then reduce the length. 
It is an in-place algorithm -does not allocates memory, too bad for the garbage collector-, and it has very good best/average/worst case behaviour.</p>

<p>This solution, compared to others here, is between 2 to 50 times faster on Chrome, and 5 to 50 times faster on Firefox, as you might see here : <a href="http://jsperf.com/remove-null-items-from-array" rel="nofollow">http://jsperf.com/remove-null-items-from-array</a></p>

<p>The code below adds the non-enumerable 'removeNull' method to the Array, which returns 'this' for daisy-chaining : </p>

<pre><code>var removeNull = function() {
    var nullCount = 0           ;
    var length    = this.length ;
    for (var i=0, len=this.length; i&lt;len; i++) { if (!this[i]) {nullCount++} }
    // no item is null
    if (!nullCount) { return this}
    // all items are null
    if (nullCount == length) { this.length = 0; return this }
    // mix of null // non-null
    var idest=0, isrc=length-1;
    length -= nullCount ;                
    while (true) {
         // find a non null (source) slot on the right
         while (!this[isrc])  { isrc--; nullCount--; } 
         if    (!nullCount) { break }       // break if found all null
         // find one null slot on the left (destination)
         while ( this[idest]) { idest++  }  
         // perform copy
         this[idest]=this[isrc];
         if (!(--nullCount)) {break}
         idest++;  isrc --; 
    }
    this.length=length; 
    return this;
};  

Object.defineProperty(Array.prototype, 'removeNull', 
                { value : removeNull, writable : true, configurable : true } ) ;
</code></pre>


blocks|key|1692591|text|这是可行的，我在AppJet中对其进行了测试(你可以将代码复制粘贴到它的集成开发环境中，然后按“重新加载”来查看它的工作，不需要创建帐户)|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1692592|/*+appjet:version+0.1+*/
function+Joes_remove(someArray)+{
++++var+newArray+=+[];
++++var+element;
++++for(+element+in+someArray){
++++++++if(someArray[element]!=undefined+)+{
++++++++++++newArray.push(someArray[element]);
++++++++}
++++}
++++return+newArray;
}

var+myArray2+=+[1,2,,3,,3,,,0,,,4,,4,,5,,6,,,,];

print("Original+array:",+myArray2);
print("Clenased+array:",+Joes_remove(myArray2)+);
/*
Returns:+[1,2,3,3,0,4,4,5,6]
*/|code-block|syntax|javascript|1692593|entityMap|0|LINK|mutability|MUTABLE|url|http://appjet.com/^0|8|6|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@$A|R|B|S|1|T]]|C|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|C|$G|H]]|$1|I|3|-4|5|6|7|V|8|@]|9|@]|C|$]]]|J|$K|$5|L|M|N|C|$O|P]]]]

<p>This works, I tested it in <a href="http://appjet.com/" rel="nofollow noreferrer">AppJet</a> (you can copy-paste the code on its IDE and press "reload" to see it work, don't need to create an account)</p>

<pre><code>/* appjet:version 0.1 */
function Joes_remove(someArray) {
    var newArray = [];
    var element;
    for( element in someArray){
        if(someArray[element]!=undefined ) {
            newArray.push(someArray[element]);
        }
    }
    return newArray;
}

var myArray2 = [1,2,,3,,3,,,0,,,4,,4,,5,,6,,,,];

print("Original array:", myArray2);
print("Clenased array:", Joes_remove(myArray2) );
/*
Returns: [1,2,3,3,0,4,4,5,6]
*/
</code></pre>


blocks|key|1693292|text|“滥用”for+..。in+(对象-成员)循环。=>只有真值才会出现在循环体中。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1693293|//+---+Example+----------
var+field+=+[];

field[0]+=+'One';
field[1]+=+1;
field[3]+=+true;
field[5]+=+43.68;
field[7]+=+'theLastElement';
//+---+Example+----------

var+originalLength;

//+Store+the+length+of+the+array.
originalLength+=+field.length;

for+(var+i+in+field)+{
++//+Attach+the+truthy+values+upon+the+end+of+the+array.+
++field.push(field[i]);
}

//+Delete+the+original+range+within+the+array+so+that
//+only+the+new+elements+are+preserved.
field.splice(0,+originalLength);|code-block|syntax|javascript|1693294|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>'Misusing' the for ... in (object-member) loop.
  => Only truthy values appear in the body of the loop.</p>

<pre><code>// --- Example ----------
var field = [];

field[0] = 'One';
field[1] = 1;
field[3] = true;
field[5] = 43.68;
field[7] = 'theLastElement';
// --- Example ----------

var originalLength;

// Store the length of the array.
originalLength = field.length;

for (var i in field) {
  // Attach the truthy values upon the end of the array. 
  field.push(field[i]);
}

// Delete the original range within the array so that
// only the new elements are preserved.
field.splice(0, originalLength);
</code></pre>


blocks|key|1694019|text|可以通过简单地使用array.filter(String);从数组中删除所有空元素，它返回javascript中数组的所有非空元素|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1694020|entityMap^0|9|L|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|K|8|@]|D|@]|E|$]]]|G|$]]

<p>All the empty elements can be removed from an array by simply by using
<code>array.filter(String);</code>
It returns all non empty elements of an array in javascript</p>


blocks|key|1693615|text|这个函数只会删除空值，而不会删除错误的值，我认为这更可取。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1693616|也有一个删除空值的选项。|1693617|这种方法应该比使用splice快得多。|1693618|++++function+cleanArray(a,+removeNull)+{
++++++++var+i,+l,+temp+=+[];
++++++++l+=+a.length;
++++++++if+(removeNull)+{
++++++++++++for+(i+=+0;+i+<+l;+i%2B%2B)+{
++++++++++++++++if+(a[i]+!==+undefined+&&+a[i]+!==+null)+{
++++++++++++++++++++temp.push(a[i]);
++++++++++++++++}
++++++++++++}
++++++++}+else+{
++++++++++++for+(i+=+0;+i+<+l;+i%2B%2B)+{
++++++++++++++++if+(a[i]+!==+undefined)+{
++++++++++++++++++++temp.push(a[i]);
++++++++++++++++}
++++++++++++}
++++++++}
++++++++a.length+=+0;
++++++++l+=+temp.length;
++++++++for+(i+=+0;+i+<+l;+i%2B%2B)+{
++++++++++++a[i]+=+temp[i];
++++++++}
++++++++temp.length+=+0;
++++++++return+a;
++++}
++++var+myArray+=+[1,+2,+,+3,+,+3,+,+,+0,+,+null,+false,+,+NaN,+'',+4,+,+4,+,+5,+,+6,+,+,+,+];
++++cleanArray(myArray);
++++myArray;|code-block|syntax|javascript|1693619|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|N|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|O|8|@]|9|@]|A|$]]|$1|F|3|G|5|H|7|P|8|@]|9|@]|A|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

<p>This one will only remove empty values and not falsey ones, which I think is more desirable.</p>

<p>There is an option to also remove null values.</p>

<p>This method should be much faster than using splice.</p>

<pre><code>    function cleanArray(a, removeNull) {
        var i, l, temp = [];
        l = a.length;
        if (removeNull) {
            for (i = 0; i &lt; l; i++) {
                if (a[i] !== undefined &amp;&amp; a[i] !== null) {
                    temp.push(a[i]);
                }
            }
        } else {
            for (i = 0; i &lt; l; i++) {
                if (a[i] !== undefined) {
                    temp.push(a[i]);
                }
            }
        }
        a.length = 0;
        l = temp.length;
        for (i = 0; i &lt; l; i++) {
            a[i] = temp[i];
        }
        temp.length = 0;
        return a;
    }
    var myArray = [1, 2, , 3, , 3, , , 0, , null, false, , NaN, '', 4, , 4, , 5, , 6, , , , ];
    cleanArray(myArray);
    myArray;
</code></pre>


blocks|key|1693670|text|使用filter删除数组中的空字符串。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1693671|​|1693672|var+s+=+[+'1,201,karthikeyan,K201,HELPER,karthikeyan.a@limitlessmobil.com,8248606269,7/14/2017,45680,TN-KAR24,8,800,1000,200,300,Karthikeyan,11/24/2017,Karthikeyan,11/24/2017,AVAILABLE\r',
++''+]
var+newArr+=+s.filter(function(entry)+{+return+entry.trim()+!=+'';+})

console.log(newArr);+|code-block|syntax|javascript|1693673|1693674|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>use filter to remove empty string in array.</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>var s = [ '1,201,karthikeyan,K201,HELPER,karthikeyan.a@limitlessmobil.com,8248606269,7/14/2017,45680,TN-KAR24,8,800,1000,200,300,Karthikeyan,11/24/2017,Karthikeyan,11/24/2017,AVAILABLE\r',
  '' ]
var newArr = s.filter(function(entry) { return entry.trim() != ''; })

console.log(newArr); </code></pre>
</div>
</div>
</p>


blocks|key|1693848|text|就地解决方案：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1693849|function+pack(arr)+{+//+remove+undefined+values
++let+p+=+-1
++for+(let+i+=+0,+len+=+arr.length;+i+<+len;+i%2B%2B)+{
++++if+(arr[i]+!==+undefined)+{+if+(p+>=+0)+{+arr[p]+=+arr[i];+p%2B%2B+}+}
++++else+if+(p+<+0)+p+=+i
++}
++if+(p+>=+0)+arr.length+=+p
++return+arr
}

let+a+=+[1,+2,+3,+undefined,+undefined,+4,+5,+undefined,+null]
console.log(JSON.stringify(a))
pack(a)
console.log(JSON.stringify(a))|code-block|syntax|javascript|1693850|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>An in place solution:</p>

<pre><code>function pack(arr) { // remove undefined values
  let p = -1
  for (let i = 0, len = arr.length; i &lt; len; i++) {
    if (arr[i] !== undefined) { if (p &gt;= 0) { arr[p] = arr[i]; p++ } }
    else if (p &lt; 0) p = i
  }
  if (p &gt;= 0) arr.length = p
  return arr
}

let a = [1, 2, 3, undefined, undefined, 4, 5, undefined, null]
console.log(JSON.stringify(a))
pack(a)
console.log(JSON.stringify(a))
</code></pre>


blocks|key|1478791|text|如果你使用的是NodeJS，你可以使用clean-deep包。之前使用npm+i+clean-deep。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1478792|const+cleanDeep+=+require('clean-deep');
var+array+=+[0,+1,+null,+2,+"",+3,+undefined,+3,,,,,,+4,,+4,,+5,,+6,,,,];
const+filterd+=+cleanDeep(array);
console.log(filterd);|code-block|syntax|javascript|1478793|entityMap|0|LINK|mutability|MUTABLE|url|https://www.npmjs.com/package/clean-deep^0|Z|G|J|A|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@$9|V|A|W|1|X]]|E|$]]|$1|F|3|G|5|H|7|Y|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Z|8|@]|D|@]|E|$]]]|L|$M|$5|N|O|P|E|$Q|R]]]]

<p>If you're using NodeJS, you can use <a href="https://www.npmjs.com/package/clean-deep" rel="nofollow noreferrer">clean-deep</a> package.
Use <code>npm i clean-deep</code> before.</p>
<pre><code>const cleanDeep = require('clean-deep');
var array = [0, 1, null, 2, &quot;&quot;, 3, undefined, 3,,,,,, 4,, 4,, 5,, 6,,,,];
const filterd = cleanDeep(array);
console.log(filterd);
</code></pre>


blocks|key|1478870|text|上面的答案没有一种对所有类型都有效。下面的解决方案将删除空的，未定义的，{}+[]，NaN，并将保留日期字符串，最好的是它甚至从嵌套对象中删除。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1478871|function+removeNil(obj)+{
++++//+recursively+remove+null+and+undefined+from+nested+object+too.
++++return+JSON.parse(JSON.stringify(obj),+(k,v)+=>+{
++++++if(v+===+null+%7C%7C+v+===+'')+return+undefined;
++++++//+convert+date+string+to+date.
++++++if+(typeof+v+===+"string"+&&+/%5E\d\d\d\d-\d\d-\d\dT\d\d:\d\d:\d\d.\d\d\dZ$/.test(v))
++++++++return+new+Date(v);
++++++//+remove+empty+array+and+object.
++++++if(typeof+v+===+'object'+&&+!Object.keys(v).length)+return+undefined;
++++++return+v;
++++});
++}|code-block|syntax|javascript|1478872|​|1478873|function+removeNil(obj)+{
++++//+recursively+remove+null+and+undefined+from+nested+object+too.
++++return+JSON.parse(JSON.stringify(obj),+(k,v)+=>+{
++++++if(v+===+null+%7C%7C+v+===+'')+return+undefined;
++++++//+convert+date+string+to+date.
++++++if+(typeof+v+===+"string"+&&+/%5E\d\d\d\d-\d\d-\d\dT\d\d:\d\d:\d\d.\d\d\dZ$/.test(v))
++++++++return+new+Date(v);
++++++//+remove+empty+array+and+object.
++++++if(typeof+v+===+'object'+&&+!Object.keys(v).length)+return+undefined;
++++++return+v;
++++});
++}
++
+const+ob+=+{
++s:+'a',
++b:+43,
++countries:+[+'a',+'b',+'c'+],
++l:+null,
++n:+{+ks:+'a',+efe:+null,+ce:+''+},
++d:+new+Date(),
++nan:+NaN,
++k:+undefined,
++emptyO:+{},
++emptyArr:+[],
+}
+
+const+output+=+removeNil(ob);
+
+console.log(output);
+console.log('Tests:+',+ob.countries.length,+typeof(ob.d))|1478874|1478875|entityMap^0|10|2|13|2|16|3|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|R|8|@$9|S|A|T|B|C]|$9|U|A|V|B|C]|$9|W|A|X|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|Y|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|Z|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|10|8|@]|D|@]|E|$I|J]]|$1|O|3|L|5|6|7|11|8|@]|D|@]|E|$]]|$1|P|3|-4|5|6|7|12|8|@]|D|@]|E|$]]]|Q|$]]

<p>None of the answers above works best for all types. The below solution will remove null, undefined, <code>{}</code> <code>[]</code>, <code>NaN</code> and will preserve date string and what's best is it removes even from nested objects.</p>
<pre><code>function removeNil(obj) {
    // recursively remove null and undefined from nested object too.
    return JSON.parse(JSON.stringify(obj), (k,v) =&gt; {
      if(v === null || v === '') return undefined;
      // convert date string to date.
      if (typeof v === &quot;string&quot; &amp;&amp; /^\d\d\d\d-\d\d-\d\dT\d\d:\d\d:\d\d.\d\d\dZ$/.test(v))
        return new Date(v);
      // remove empty array and object.
      if(typeof v === 'object' &amp;&amp; !Object.keys(v).length) return undefined;
      return v;
    });
  }
</code></pre>
<p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="true">
<div class="snippet-code">
<pre class="snippet-code-js lang-js prettyprint-override"><code>function removeNil(obj) {
    // recursively remove null and undefined from nested object too.
    return JSON.parse(JSON.stringify(obj), (k,v) =&gt; {
      if(v === null || v === '') return undefined;
      // convert date string to date.
      if (typeof v === "string" &amp;&amp; /^\d\d\d\d-\d\d-\d\dT\d\d:\d\d:\d\d.\d\d\dZ$/.test(v))
        return new Date(v);
      // remove empty array and object.
      if(typeof v === 'object' &amp;&amp; !Object.keys(v).length) return undefined;
      return v;
    });
  }
  
 const ob = {
  s: 'a',
  b: 43,
  countries: [ 'a', 'b', 'c' ],
  l: null,
  n: { ks: 'a', efe: null, ce: '' },
  d: new Date(),
  nan: NaN,
  k: undefined,
  emptyO: {},
  emptyArr: [],
 }
 
 const output = removeNil(ob);
 
 console.log(output);
 console.log('Tests: ', ob.countries.length, typeof(ob.d))</code></pre>
</div>
</div>
</p>


blocks|key|1477498|text|使用正则表达式过滤掉无效条目|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1477499|array+=+array.filter(/\w/);
filter+%2B+regexp|code-block|syntax|javascript|1477500|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>Filtering out invalid entries with a regular expression</p>

<pre><code>array = array.filter(/\w/);
filter + regexp
</code></pre>


blocks|key|1693804|text|这是我清理空字段的解决方案。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1693805|从费用对象开始:仅获取avail属性(使用map)过滤空字段(使用filter)将结果解析为整数(使用map)|1693806|fees.map(+(+e+)+=>+e.avail+).filter(+v+=>+v!==+'').map(+i+=>+parseInt(+i+)+);|code-block|syntax|javascript|1693807|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|L|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|M|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

<p>this is my solution for clean empty fields.</p>

<p>Start from fees object:
get only avail attribute (with map)
filter empty fields (with filter)
parse results to integer (with map)</p>

<pre><code>fees.map( ( e ) =&gt; e.avail ).filter( v =&gt; v!== '').map( i =&gt; parseInt( i ) );
</code></pre>


blocks|key|1478527|text|var+a+=+[{a1:+1,+children:+[{a1:+2},+undefined,+{a1:+3}]},+undefined,+{a1:+5},+undefined,+{a1:+6}]
function+removeNilItemInArray(arr)+{
++++if+(!arr+%7C%7C+!arr.length)+return;
++++for+(let+i+=+0;+i+<+arr.length;+i%2B%2B)+{
++++++++if+(!arr[i])+{
++++++++++++arr.splice(i+,+1);
++++++++++++continue;
++++++++}
++++++++removeNilItemInArray(arr[i].children);
++++}
}
var+b+=+a;
removeNilItemInArray(a);
//+Always+keep+this+memory+zone
console.log(b);|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1478528|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 a = [{a1: 1, children: [{a1: 2}, undefined, {a1: 3}]}, undefined, {a1: 5}, undefined, {a1: 6}]
function removeNilItemInArray(arr) {
    if (!arr || !arr.length) return;
    for (let i = 0; i &lt; arr.length; i++) {
        if (!arr[i]) {
            arr.splice(i , 1);
            continue;
        }
        removeNilItemInArray(arr[i].children);
    }
}
var b = a;
removeNilItemInArray(a);
// Always keep this memory zone
console.log(b);
</code></pre>


blocks|key|1694211|text|//+recursive+implementation
function+compact(arr)+{
++++++++const+compactArray+=+[];
++++++++//base+case+
++++++++if(!arr.length)+return+[]
++++++++if(typeof+arr[0]+!==+"undefined"+
++++++++++&&+arr[0]!==null+&&+arr[0]+!==+"+"+&&+
++++++++++arr[0]!==+false+&&
++++++++++arr[0]!==+0){
++++++++++compactArray.push(arr[0]);
++++++++}
++++++++return+compactArray.concat(compact(arr.slice(1)))
++++}
++++
++++compact([1,0,false,null,undefined,"banana"])`|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1694212|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>// recursive implementation
function compact(arr) {
        const compactArray = [];
        //base case 
        if(!arr.length) return []
        if(typeof arr[0] !== &quot;undefined&quot; 
          &amp;&amp; arr[0]!==null &amp;&amp; arr[0] !== &quot; &quot; &amp;&amp; 
          arr[0]!== false &amp;&amp;
          arr[0]!== 0){
          compactArray.push(arr[0]);
        }
        return compactArray.concat(compact(arr.slice(1)))
    }
    
    compact([1,0,false,null,undefined,&quot;banana&quot;])`
</code></pre>


blocks|key|1693142|text|不错..。非常好，我们也可以像这样替换所有的数组值|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1693143|Array.prototype.ReplaceAllValues+=+function(OldValue,newValue)
{
++++for(+var+i+=+0;+i+<+this.length;+i%2B%2B+)++
++++{
++++++++if(+this[i]+==+OldValue+)+++++++
++++++++{
++++++++++++this[i]+=+newValue;
++++++++}
++++}
};|code-block|syntax|javascript|1693144|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>Nice ... very nice 
We can also replace all array values like this</p>

<pre><code>Array.prototype.ReplaceAllValues = function(OldValue,newValue)
{
    for( var i = 0; i &lt; this.length; i++ )  
    {
        if( this[i] == OldValue )       
        {
            this[i] = newValue;
        }
    }
};
</code></pre>


blocks|key|1477987|text|下面是一个使用变量行为和ES2015胖箭头表达式的示例：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1477988|Array.prototype.clean+=+function()+{
++var+args+=+[].slice.call(arguments);
++return+this.filter(item+=>+args.indexOf(item)+===+-1);
};

//+Usage
var+arr+=+["",+undefined,+3,+"yes",+undefined,+undefined,+""];
arr.clean(undefined);+//+["",+3,+"yes",+""];
arr.clean(undefined,+"");+//+[3,+"yes"];|code-block|syntax|javascript|1477989|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>Here is an example using variadic behavior &amp; ES2015 fat arrow expression:</p>

<pre><code>Array.prototype.clean = function() {
  var args = [].slice.call(arguments);
  return this.filter(item =&gt; args.indexOf(item) === -1);
};

// Usage
var arr = ["", undefined, 3, "yes", undefined, undefined, ""];
arr.clean(undefined); // ["", 3, "yes", ""];
arr.clean(undefined, ""); // [3, "yes"];
</code></pre>


blocks|key|1692855|text|我也需要做同样的事情，于是我发现了这个帖子。我最后使用数组"join“创建了一个字符串，并使用"_”分隔符，然后执行了一些正则表达式来：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1692856|1.+replace+"__"+or+more+with+just+one+"_",
2.+replace+preceding+"_"+with+nothing+""+and+similarly+
3.+replace+and+ending+"_"+with+nothing+""|code-block|syntax|javascript|1692857|...then使用数组"split“来创建一个清理过的数组：-|1692858|var+myArr+=+new+Array("","","a","b","","c","","","","","","","","","e","");
var+myStr+=+"";

myStr+=+myArr.join("_");

myStr+=+myStr.replace(new+RegExp(/__*/g),"_");
myStr+=+myStr.replace(new+RegExp(/%5E_/i),"");
myStr+=+myStr.replace(new+RegExp(/_$/i),"");
myArr+=+myStr.split("_");

alert("myArr="+%2B+myArr.join(","));|1692859|1行代码中的...or：-|1692860|var+myArr+=+new+Array("","","a","b","","c","","","","","","","","","e","");

myArr+=+myArr.join("_").replace(new+RegExp(/__*/g),"_").replace(new+RegExp(/%5E_/i),"").replace(new+RegExp(/_$/i),"").split("_");

alert("myArr="+%2B+myArr.join(","));|1692861|...or，扩展数组对象:-|1692862|Array.prototype.clean+=+function()+{
++return+this.join("_").replace(new+RegExp(/__*/g),"_").replace(new+RegExp(/%5E_/i),"").replace(new+RegExp(/_$/i),"").split("_");
};

var+myArr+=+new+Array("","","a","b","","c","","","","","","","","","e","");

alert("myArr="+%2B+myArr.clean().join(","));|1692863|entityMap^0|0|0|0|0|0|0|0|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]]|$1|G|3|H|5|6|7|W|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|Y|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|Z|8|@]|9|@]|A|$E|F]]|$1|O|3|P|5|6|7|10|8|@]|9|@]|A|$]]|$1|Q|3|R|5|D|7|11|8|@]|9|@]|A|$E|F]]|$1|S|3|-4|5|6|7|12|8|@]|9|@]|A|$]]]|T|$]]

<p>I needed to do this same task and came upon this thread. I ended up using the array "join" to create a string using a "_" separator, then doing a bit of regex to:-</p>

<pre><code>1. replace "__" or more with just one "_",
2. replace preceding "_" with nothing "" and similarly 
3. replace and ending "_" with nothing ""
</code></pre>

<p>...then using array "split" to make a cleaned-up array:-</p>

<pre><code>var myArr = new Array("","","a","b","","c","","","","","","","","","e","");
var myStr = "";

myStr = myArr.join("_");

myStr = myStr.replace(new RegExp(/__*/g),"_");
myStr = myStr.replace(new RegExp(/^_/i),"");
myStr = myStr.replace(new RegExp(/_$/i),"");
myArr = myStr.split("_");

alert("myArr=" + myArr.join(","));
</code></pre>

<p>...or in 1 line of code:-</p>

<pre><code>var myArr = new Array("","","a","b","","c","","","","","","","","","e","");

myArr = myArr.join("_").replace(new RegExp(/__*/g),"_").replace(new RegExp(/^_/i),"").replace(new RegExp(/_$/i),"").split("_");

alert("myArr=" + myArr.join(","));
</code></pre>

<p>...or, extending the Array object :-</p>

<pre><code>Array.prototype.clean = function() {
  return this.join("_").replace(new RegExp(/__*/g),"_").replace(new RegExp(/^_/i),"").replace(new RegExp(/_$/i),"").split("_");
};

var myArr = new Array("","","a","b","","c","","","","","","","","","e","");

alert("myArr=" + myArr.clean().join(","));
</code></pre>


blocks|key|1477890|text|这是另一种方法：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1477891|var+arr+=+["a",+"b",+undefined,+undefined,+"e",+undefined,+"g",+undefined,+"i",+"",+"k"]
var+cleanArr+=+arr.join('.').split(/\.%2B/);|code-block|syntax|javascript|1477892|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>This is another way to do it:</p>

<pre><code>var arr = ["a", "b", undefined, undefined, "e", undefined, "g", undefined, "i", "", "k"]
var cleanArr = arr.join('.').split(/\.+/);
</code></pre>


blocks|key|1692366|text|尝尝这个。将数组传递给它，它将返回删除了空元素的值。*已更新以解决Jason指出的错误|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1692367|function+removeEmptyElem(ary)+{
++++for+(var+i+=+ary.length+-+1;+i+>=+0;+i--)+{
++++++++if+(ary[i]+==+undefined)++{
++++++++++++ary.splice(i,+1);
++++++++}+++++++
++++}
++++return+ary;
}|code-block|syntax|javascript|1692368|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>Try this.  Pass it your array and it will return with empty elements removed.  *Updated to address the bug pointed out by Jason</p>

<pre><code>function removeEmptyElem(ary) {
    for (var i = ary.length - 1; i &gt;= 0; i--) {
        if (ary[i] == undefined)  {
            ary.splice(i, 1);
        }       
    }
    return ary;
}
</code></pre>


blocks|key|1478190|text|这样做怎么样？|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1478191|//+Removes+all+falsy+values+
arr+=+arr.filter(function(array_val)+{+//+creates+an+anonymous+filter+func
++++var+x+=+Boolean(array_val);+//+checks+if+val+is+null
++++return+x+==+true;+//+returns+val+to+array+if+not+null
++});|code-block|syntax|javascript|1478192|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>How about doing it this way 
</p>

<pre><code>// Removes all falsy values 
arr = arr.filter(function(array_val) { // creates an anonymous filter func
    var x = Boolean(array_val); // checks if val is null
    return x == true; // returns val to array if not null
  });
</code></pre>


<p>How do I remove empty elements from an array in JavaScript? </p>

<p>Is there a straightforward way, or do I need to loop through it and remove them manually?</p>


Remove empty elements from an array in Javascript

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如何在JavaScript中删除数组中的空元素？有没有一种简单的方法，或者我需要遍历它并手动删除它们？

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