我的版本

function camelToSpace (txt) {
  return txt
    .replace(/([^A-Z]*)([A-Z]*)([A-Z])([^A-Z]*)/g, '$1 $2 $3$4')
    .replace(/ +/g, ' ')
}
camelToSpace("camelToSpaceWithTLAStuff") //=> "camel To Space With TLA Stuff"

Lodash用_.startCase()很好地处理了这个问题

不是正则表达式，但知道这些简单而古老的技巧是有用的:

var origString = "thisString";
var newString = origString.charAt(0).toUpperCase() + origString.substring(1);

"thisStringIsGood"
    // insert a space before all caps
    .replace(/([A-Z])/g, ' $1')
    // uppercase the first character
    .replace(/^./, function(str){ return str.toUpperCase(); })

显示

This String Is Good

(function() { const textbox = document.querySelector('#textbox') const result = document.querySelector('#result') function split() { result.innerText = textbox.value // insert a space before all caps .replace(/([A-Z])/g, ' $1') // uppercase the first character .replace(/^./, (str) => str.toUpperCase()) }; textbox.addEventListener('input', split); split(); }()); #result { margin-top: 1em; padding: .5em; background: #eee; white-space: pre; } <div> Text to split <input id="textbox" value="thisStringIsGood" /> </div> <div id="result"></div>

我的版本

function camelToSpace (txt) {
  return txt
    .replace(/([^A-Z]*)([A-Z]*)([A-Z])([^A-Z]*)/g, '$1 $2 $3$4')
    .replace(/ +/g, ' ')
}
camelToSpace("camelToSpaceWithTLAStuff") //=> "camel To Space With TLA Stuff"

一个处理数字的解决方案:

function capSplit(str){
   return str.replace(
      /(^[a-z]+)|[0-9]+|[A-Z][a-z]+|[A-Z]+(?=[A-Z][a-z]|[0-9])/g,
      function(match, first){
          if (first) match = match[0].toUpperCase() + match.substr(1);
          return match + ' ';
          }
       )
   }

测试在这里[JSFiddle，没有库。没有尝试IE];应该很稳定。