仅在句子的开头和结尾处替换空格

Question

有人知道如何使用正则表达式和javascript;用＆nbsp替换字符串开头和结尾的空格吗？

示例：

`   Hello World. The white spaces in between the sentence should not be replaced. Only the start and end should be replaced with &nbsp.   `

更换后：

`   Hello World. The white spaces in between the sentence should not be replaced. Only the start and end should be replaced with &nbsp.   `

Answer 1

您需要首先捕获space，然后在replace的回调函数中可以添加no。的 根据匹配的长度。

• ^\s+-匹配字符串开头的空格。
• |-与逻辑OR相同。
• \s+$-匹配字符串末尾的空格

let str = `   Hello World. The white spaces in between the sentence should not be replaced. Only the start and end should be replaced with &nbsp.   `

let op = str.replace(/^\s+|\s+$/g, function(match){
  return ` `.repeat(match.length)
})

console.log(op)