let str = "January,February,March,April,May,June,July,August,September,October,November,December"

let arr = str.split(',');

这将导致：

["January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"]

如果要将以下内容转换为：

["January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"]

这：

"January,February,March,April,May,June,July,August,September,October,November,December";

use:

str = arr.join(',')

正如@oportocala所提到的，空字符串不会产生预期的空数组。

因此，要反击，请执行以下操作：

str
.split(',')
.map(entry => entry.trim())
.filter(entry => entry)

对于预期整数数组，请执行以下操作：

str
.split(',')
.map(entry => parseInt(entry))
.filter(entry => typeof entry ==='number')

下面是一个函数，它将字符串转换为数组，即使列表中只有一项（没有分隔符）：

function listToAray(fullString, separator) {
  var fullArray = [];

  if (fullString !== undefined) {
    if (fullString.indexOf(separator) == -1) {
      fullArray.push(fullString);
    } else {
      fullArray = fullString.split(separator);
    }
  }

  return fullArray;
}

这样使用：

var myString = 'alpha,bravo,charlie,delta';
var myArray = listToArray(myString, ',');
myArray[2]; // charlie

var yourString = 'echo';
var yourArray = listToArray(yourString, ',');
yourArray[0]; // echo

我创建这个函数是因为如果字符串中没有分隔符（只有一个项目），split会抛出一个错误。

请注意：

var a = "";
var x = new Array();
x = a.split(",");
alert(x.length);

将提醒1

一个很好的解决方案：

let obj = ['A','B','C']

obj.map((c) => { return c. }).join(', ')

对于逗号分隔字符串的字符串数组：

let months = ["January","Feb"];
let monthsString = months.join(", ");