是否可以在替换方法中传递变量而不是常数

Question

在下面的代码中，逗号每3位

{
  var commaString = valueWthOutComma.replace(/\B(?=(\d{3})+(?!\d))/g, ",");
}

是否可以在上述RegEx中传递任何变量代替“ 3”

{
  var comma_place = 2 ; //any value can be place
  var commaString = valueWthOutComma.replace(/\B(?=(\d{comma_place})+(?!\d))/g, ",");
}

Answer 1

要执行所需的操作，您需要将正则表达式构建为字符串而不是文字，并将其提供给RegExp()构造函数，如下所示：

var comma_place = 2; //any value can be place
var re = new RegExp('\B(?=(\d{' + comma_place + '})+(?!\d))', 'g');
// var re = new RegExp(`\B(?=(\d{${comma_place}})+(?!\d))`, 'g'); // ES6 - won't work in IE
var commaString = valueWthOutComma.replace(re, ",");