正則表達式，只允許在名字/姓氏驗證中使用一個空格

Question

我正在嘗試編寫一個正則表達式以從單詞的開頭而不是單詞后面刪除空格，並且僅在單詞后面刪除一個空格。

使用過的RegExp：

var re = new RegExp(/^([a-zA-Z0-9]+\s?)*$/);

測試實例：

1) test[space]ing - Should be allowed 
2) testing - Should be allowed 
3) [space]testing - Should be allowed but have to trim the space at the first
4) testing[space] - Should be allowed but have to trim the space at the last 
5) testing[space][space] - should be allowed but have to trim the space at the last  
6) test[space][space]ing - one space should be allowed but the remaining spaces have to be trimmed.

知道使用正則表達式如何實現嗎？

編輯：

我有這個，

 var regExp = /^(\w+\s?)*\s*$/;
if(regExp.test($('#FirstName').val())){
                    $('#FirstName').val().replace(/\s+$/, '');
                }else{
                    var elm = $('#FirstName'),
                    msg = 'First Name must consist of letters with no spaces';
                    return false;
                }

Answer 1

使用捕獲組：

var re = /^\s+|\s+$|(\s)\s+/g;
'test ing'.replace(re, '$1')   // => 'test ing'
'testing'.replace(re, '$1')    // => 'testing'
' testing'.replace(re, '$1')   // => 'testing'
'testing '.replace(re, '$1')   // => 'testing'
'testing  '.replace(re, '$1')  // => 'testing'
'test  ing'.replace(re, '$1')  // => 'test ing'

Answer 2

我可能會懶於保持簡單並使用兩個單獨的RE：

// Collapse any multiple spaces into one - handles cases 5 & 6
str.replace(/ {2,}/, ' ');

// Trim any leading space
str.replace(/^ /, '');

或者，作為一個陳述：

var result = str.replace(/ {2,}/, ' ').replace(/^ ?/, '');

Answer 3

這個怎么樣：

replace(/^ | $|( ) +/, $1)?