JSFiddle - React, Tailwind, and code Playground

HTML

<textarea>Test</textarea>
<div>Test</div>

CSS

div { background-color: blue; position: absolute;}

JavaScript

$("textarea").bind("resize", function() {
    $("div").css('width', $(this).css('width'));
    $("div").css('height', $(this).css('height'));
});
$("textarea").bind('mousedown.shiftenter', function(){
    // Reposition while the mouse is down, use might have clicked on resize handler
    $(this).bind('mousemove.shiftenter', function() {
        var $el = $(this);
        var old_size = $el.data('textarea_resize');
        if (!old_size) {
            $el.trigger('resize');
        } else {
            var new_size = {width: $el.width(), height: $el.height()};
            if (old_size.width != new_size.width || old_size.height != new_size.height) {
                $el.trigger('resize');
                $el.data('textarea_resize', new_size);
            }
        }
    });
});
$("textarea").bind('mouseup.shiftenter', function(){
    $("textarea").unbind('mousemove.shiftenter');
});