如何简化正则？

Question

function excludeSubstring(inputString, substringToDelete) {
  const regex = new RegExp(
    `(^\\b${substringToDelete}\\b,*)|(,*\\b${substringToDelete}\\b)`
  );
  return inputString.replace(regex, "");
}

// 举例
'12,34,56'.replace(/(^12,*)|(,*12)/,'')

如何简化这个正则呢？
或者是否有其他实现方式(正则)？

Answer 1

用零宽断言
/(?<=^|,)12(?=,|$)/

'12,34,56,12,34,56,12'.replace(/(?<=^|,)12(?=,|$)/g, '[]')

结果是 [],34,56,[],34,56,[]

删除的话，正则改一下，需要一点点额外 JS 辅助一下

'12,34,56,12,34,56,12'.replace(/(^|,)12(,|$)/g, function($0, $1, $2){
    // console.log($0, $1, $2);
    return ($1===$2 ? ',' : '');
})

结果是 34,56,34,56

Answer 2

如果已知字符串都是 , 隔开的话，可以直接转换为数组过滤，没必要使用正则，这种过滤的方式应该比正则更容易理解吧

let string = '12,34,56,12';

function excludeSubstring(inputString,substringToDelete){
   return inputString.split(',').filter(item => item !== substringToDelete).join(',');
}

excludeSubstring(string,'12');

Answer 3

  const regex = new RegExp(
    `\\b${substringToDelete}\\b,|,${substringToDelete}\\b`
  );