In vue.js component, how to use props in css?

Question

I'm new to vue.js. Here is my problem:

In a *.vue file like this:

<template>
  <div id="a">
  </div>
</template>

<script>
  export default {
    name: 'SquareButton',
    props: ['color']
  }
</script>

<style scoped>
    #a {
      background-color: ?
    }
<style>

How can I use the props color in background-color: (where is a ? now).

Thanks.

Answer 1

You actually can!

You should define the CSS variables in a Computed Property, then call the computed property as a style attribute to the element that will require the CSS variable, and finally you may use the variable within the tags at the bottom of your document.

new Vue({
  el: '#app',
  data: function() {
    return {
      baseFontSize: 1,
      bgHoverColor: "#00cc00",
      hoverContent: "Hovering!"
    }
  },
  computed: {
    cssProps() {
      return {
        '--hover-font-size': (this.baseFontSize * 2) + "em",
        '--bg-hover-color': this.bgHoverColor,
        '--hover-content': JSON.stringify(this.hoverContent)
      }
    }
  }
})

div {
  margin: 1em;
}

div.test:hover {
  background-color: var(--bg-hover-color);
  font-size: var(--hover-font-size);
}

div.test:hover::after {
  margin-left: 1em;
  content: var(--hover-content);
}

<script src="https://unpkg.com/vue/dist/vue.js"></script>

<div id="app" :style="cssProps">

  <div>Hover text: <input type="text" v-model="hoverContent"></div>
  <div>Hover color: <input type="color" v-model="bgHoverColor"></div>

  <div class="test">Hover over me</div>
</div>

Or have a look here: https://codepen.io/richardtallent/pen/yvpERW/
And here: https://github.com/vuejs/vue/issues/7346