title: vue v-bind:class return invalid value
body: <p>I am writing an application at vue and I am getting incorrect behavior, in particular my line :class=require ? 'require' : '' returns the string 'require' even when the value of require is false, what is the problem?</p>
  <pre class="lang-html prettyprint-override"><code>&lt;template&gt;
    &lt;custom-label label=&quot;Название&quot;&gt;
      &lt;input
          class=&quot;text_input&quot;
          :class=&quot;require ? 'require' : ''&quot;
          :value=&quot;$attrs.value&quot; @input=&quot;$emit('input', $event.target.value)&quot;
          placeholder=&quot;Матрица всея барановичского района&quot;
      /&gt;
    &lt;/custom-label&gt;
  &lt;/template&gt;
  
  &lt;script&gt;
  export default {
    name: &quot;InputText&quot;,
    components: {CustomLabel},
    computed: mapState({ state: state =&gt; state }),
    props: {
      require: Boolean
    }
  };
  &lt;/script&gt;
  </code></pre>
  <p>Below are screenshots from devtools</p>
  <p><img src="https://i.stack.imgur.com/2o1qK.png" alt="HTML" /></p>
  <p><img src="https://i.stack.imgur.com/5u7OC.png" alt="vue dev-tools" /></p>