JSFiddle - React, Tailwind, and code Playground

HTML

<script src="//code.jquery.com/ui/1.10.4/jquery-ui.js"></script>
<div class="ui-resizable block yellow">
    <div class="child_class block yellow"></div>
</div>
<div class="ui-resizable block blue">
    <div class="child_class block blue"></div>
</div>

CSS

.block {
    display: inline-block;
    width: 200px;
    height: 200px;
}
.yellow {
    background-color: yellow;
}
.blue {
    background-color: blue;
}

JavaScript

//custom resize resizable child v.1.0 - Alexander Dixon
//http://stackoverflow.com/questions/31845459/select-child-for-jquery-resizable-alsoresize
//08-06-2015

$(".ui-resizable").resizable({
  // alsoResize: $(this).find(".panel-body") <- doesn't work...
  resize: function(event, ui) {
    $(ui.element).find(".child_class").height(ui.size.height);
  }
});