JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://rangy.googlecode.com/svn/trunk/currentrelease/rangy-core.js"></script>
<script src="http://rangy.googlecode.com/svn/trunk/currentrelease/rangy-selectionsaverestore.js"></script>
<div id="editor" contenteditable="true" OnKeyUp="javascript:color(this);"></div>

<!-- Vous pouvez tester avec ce code les retours Ă  la ligne etc. !-->

CSS

body {
  height: 100%;
  font-family: Verdana, Open Sans, sans-serif;
}

#editor {
  display: inline-block;
  font-family: Consolas;
  font-size: 14px;
  border: 1px solid gray;
  border-radius: 3px;
  background-color: #272822;
  color: white;
  padding: 10px;
  width: 80%;
  height: 400px;
}

JavaScript

function saveSelection(containerEl) {
    var charIndex = 0, start = 0, end = 0, foundStart = false, stop = {};
    var sel = rangy.getSelection(), range;

    function traverseTextNodes(node, range) {
        if (node.nodeType == 3) {
            if (!foundStart && node == range.startContainer) {
                start = charIndex + range.startOffset;
                foundStart = true;
            }
            if (foundStart && node == range.endContainer) {
                end = charIndex + range.endOffset;
                throw stop;
            }
            charIndex += node.length;
        } else {
            for (var i = 0, len = node.childNodes.length; i < len; ++i) {
                traverseTextNodes(node.childNodes[i], range);
            }
        }
    }

    if (sel.rangeCount) {
        try {
            traverseTextNodes(containerEl, sel.getRangeAt(0));
        } catch (ex) {
            if (ex != stop) {
                throw ex;
            }
        }
    }

    return {
        start: start,
        end: end
    };
}

function restoreSelection(containerEl, savedSel) {
    var charIndex = 0, range = rangy.createRange(), foundStart = false, stop = {};
    range.collapseToPoint(containerEl, 0);

    function traverseTextNodes(node) {
        if (node.nodeType == 3) {
            var nextCharIndex = charIndex + node.length;
            if (!foundStart && savedSel.start >= charIndex && savedSel.start <= nextCharIndex) {
                range.setStart(node, savedSel.start - charIndex);
                foundStart = true;
            }
            if (foundStart && savedSel.end >= charIndex && savedSel.end <= nextCharIndex) {
                range.setEnd(node, savedSel.end - charIndex);
                throw stop;
            }
            charIndex = nextCharIndex;
        } else {
            for (var i = 0, len = node.childNodes.length; i < len; ++i) {
                traverseTextNodes(node.childNodes[i]);
            }
        }
    }

    try {
  ...