javascript - Change width proportions of two blocks with a slider

Question

I'm trying to design a component in which you could change the width proportions of two blocks by moving a slider left and right:

codpen and demo:

.outer {
  display: flex;
  flex-direction: row;
}

.block {
  height: 200px;
  width: -webkit-calc(50% - 5px);
  width: -moz-calc(50% - 5px);
  width: calc(50% - 5px);
}

.block-1 {
  background-color: red;
}

.block-2 {
  background-color: green;
}

.slider {
  line-height: 100%;
  width: 10px;
  background-color: #dee2e6;
  border: none;
  cursor: e-resize;
}

<div id="app">
  <div class="outer">
    <div class="block block-1">
      Block 1
    </div>
    <div class="slider">
      S<br>l<br>i<br>d<br>e<br>r
    </div>
    <div class="block block-2">
      Block 2
    </div>
  </div>
</div>

Answer 1

You can adjust your flexbox along with resize - the downside is that the slider its not very customizeable:

• add resize: horizontal to one of the flex items
• add flex: 1 to the other flex item (so that this flex item will adjust automatically in response to the changing width of the other flex item as it is resized)

See demo below:

.outer {
  display: flex;
  flex-direction: row;
}

.block {
  height: 100px;
  width: 50%; /* 50% would suffice*/
}

.block-1 {
  background-color: red;
  resize: horizontal; /* resize horizontal */
  overflow: hidden; /* resize works for overflow other than visible */
}

.block-2 {
  background-color: green;
  flex: 1; /* adjust automatically */
}

<div id="app">
  <div class="outer">
    <div class="block block-1">
      Block 1
    </div>
    <div class="block block-2">
      Block 2
    </div>
  </div>
</div>