javascript - 用 html 标签替换文本区域中的字符

Question

我正在构建一个具有需要格式化的文本区域的应用程序。我不想使用 contenteditable div，所以我认为下一个最佳解决方案是使用普通的文本区域，然后用标签替换字符。

格式类似于 Reddit 或 Slack..

$( '.actionBtn' ).on('click', function(){
  var cursorPos = $('#text').prop('selectionStart');
  var cursorPosEnd = $('#text').prop('selectionEnd');
  var v = $('#text').val();
  var textBefore = v.substring(0,  cursorPos );
  var textSelected  = v.substring( cursorPos, cursorPosEnd );
  if(textSelected == "") {
  	textSelected = "text here"
  }
  var textAfter  = v.substring( cursorPosEnd, v.length );
  $('#text').val( textBefore + $(this).val() + textSelected + $(this).val() + textAfter );
});

$( '#submitBtn' ).on('click', function(){
//TODO: switch to tags
  	 // * becomes <b></b>
     // _ becomes <i></i>
     // #c# becomes <span class="myClass"> </span>
  $('#result').html($('#text').val())
});

.myClass {
  color: #FF0;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<form>
    <div>
      <textarea id="text" cols="40" rows="3"></textarea>
    </div>
    <div>
      <input class="actionBtn" type="button" value="*" />
      <input class="actionBtn" type="button" value="_" />
      <input class="actionBtn" type="button" value="#c#" />
    </div>
    <div>
      <input id="submitBtn" type="button" value="Submit" />
    </div>
    <p id="result">
    
    </p>
</form>

因此，从这个示例中，当按下Submit时，我需要:

* becomes <b></b>
_ becomes <i></i>
#c# becomes <span class="myClass"> </span>

我怎样才能做到这一点？谢谢

Answer 1

您可以使用正则表达式轻松替换字符串中偶数/奇数出现的字符串。例如:

const regex = /\_(.*?)\_/gm;
const str = `Lorem _ipsum_ dolor sit amet, _consectetur adipiscing_ elit, sed 
do _eiusmod_ tempor `;
const subst = `<em>$1</em>`;

// The substituted value will be contained in the result variable
const result = str.replace(regex, subst);
console.log('Substitution result: ', result);

Check it online