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 < 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);

几个简单的方法：

var arr = [1,2,,3,,-3,null,,0,,undefined,4,,4,,5,,6,,,,];

arr.filter(n => n)
// [1, 2, 3, -3, 4, 4, 5, 6]

arr.filter(Number) 
// [1, 2, 3, -3, 4, 4, 5, 6]

arr.filter(Boolean) 
// [1, 2, 3, -3, 4, 4, 5, 6]

或-（仅适用于“text”类型的单个数组项）

['','1','2',3,,'4',,undefined,,,'5'].join('').split(''); 
// output:  ["1","2","3","4","5"]

或-经典方式：简单迭代

var arr = [1,2,null, undefined,3,,3,,,0,,,[],,{},,5,,6,,,,],
    len = arr.length, i;

for(i = 0; i < len; i++ )
    arr[i] && arr.push(arr[i]);  // copy non-empty values to the end of the array

arr.splice(0 , len);  // cut the array and leave only the non-empty values
// [1,2,3,3,[],Object{},5,6]

jQuery：

var arr = [1,2,,3,,3,,,0,,,4,,4,,5,,6,,,,];
    
arr = $.grep(arr, n => n == 0 || n);
// [1, 2, 3, 3, 0, 4, 4, 5, 6]

我需要完成同样的任务，并遇到了这个线程。我最终使用数组“join”使用“_”分隔符创建字符串，然后使用正则表达式：-

1. replace "__" or more with just one "_",
2. replace preceding "_" with nothing "" and similarly 
3. replace and ending "_" with nothing ""

…然后使用数组“拆分”生成一个已清理的数组：-

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(","));

…或1行代码：-

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(","));

…或，扩展Array对象：-

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(","));

我只是在上面的“用全局构造函数调用ES5的数组..filter（）”高尔夫技巧中添加了我的声音，但我建议使用Object而不是上面建议的String、Boolean或Number。

具体来说，ES5的filter（）已经不会为数组中未定义的元素触发；因此，一个普遍返回true（返回所有元素filter（）命中）的函数必然只返回未定义的元素：

> [1,,5,6,772,5,24,5,'abc',function(){},1,5,,3].filter(function(){return true})
[1, 5, 6, 772, 5, 24, 5, 'abc', function (){}, 1, 5, 3]

然而，写出。。。（function（）｛return true；｝）的长度大于写入。。。（对象）；在任何情况下，Object构造函数的返回值都将是某种类型的对象。与上面建议的基本装箱构造函数不同，没有可能的对象值是假的，因此在布尔设置中，object是function（）｛return true｝的缩写。

> [1,,5,6,772,5,24,5,'abc',function(){},1,5,,3].filter(Object)
[1, 5, 6, 772, 5, 24, 5, 'abc', function (){}, 1, 5, 3]

这是我清理空字段的解决方案。

从费用对象开始：仅获取可用属性（带贴图）筛选空字段（带筛选器）将结果解析为整数（带映射）

fees.map( ( e ) => e.avail ).filter( v => v!== '').map( i => parseInt( i ) );

如果需要删除所有空值（“”、null、undefined和0）：

arr = arr.filter(function(e){return e}); 

要删除空值和换行符，请执行以下操作：

arr = arr.filter(function(e){ return e.replace(/(\r\n|\n|\r)/gm,"")});

例子：

arr = ["hello",0,"",null,undefined,1,100," "]  
arr.filter(function(e){return e});

返回：

["hello", 1, 100, " "]

更新（基于Alnitak的评论）

在某些情况下，您可能希望在数组中保留“0”并删除其他任何内容（null、undefined和“”），这是一种方法：

arr.filter(function(e){ return e === 0 || e });

返回：

["hello", 0, 1, 100, " "]