Vue 3 issues importing / resolving component

Question

Hi new to Vue and learning through tutorials. I have created a component Header.vue and try to import it to App.vue. This is the structure: code structure

here is App.vue:

<template>
  <Header />
</template>

<script>
import Header  from "./components/Header.vue";

export default {
  setup() {
    return {
      Header,
    };
  },
};
</script>

<style>
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: "Fira Sans", sans-serif;
}
body {
  background: #eee;
}
</style>

Here is the Header.vue component:

<template>
  <div>
    <h1>Income Tracker</h1>
    <div class="total-income">$0</div>
  </div>
</template>

<script>
export default {

};
</script>

<style scoped>
header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 15px 30px;
  background-color: #313131;
  border-bottom: 5px solid #ffce00;
}
header h1 {
  color: #eee;
  font-size: 28px;
}
header .total-income {
  font-family: "Fira Code", "Fira Sans", sans-serif;
  background-color: #ffce00;
  color: #fff;
  font-size: 20px;
  font-weight: 900;
  padding: 5px 10px;
  min-width: 100px;
  text-align: center;
  border-radius: 8px;
  box-shadow: inset 0px 0px 6px rgba(0, 0, 0, 0.25);
  text-shadow: 0px 3px 3px rgba(0, 0, 0, 0.25);
}
</style>

I am getting the styling from the App.vue but the component isn't resolving. In the console I get this error: error message

What I have tried is stack overflow and google search based on the error message text.

Either I am not searching correctly, or I do not have enough experience at this point to identify the issue causing this problem.

Education on how to resolve this would be greatly appreciated.

Answer 1

Plain Vue

You need to register components in the components option.

export default {
  components: {
    Header,
  },
};

See the docs.

Note that including a valueless entry in a JavaScript object (e.g. Header) is ES6 syntax for Header: Header.

script setup

As Vue 3 has matured over the years, there is less and less reason to use the Options API (less and less Vue 2 code exists or remains relevant). Without the need for the Options API (using the Composition API), all code is written in the setup hook, so script setup has taken up a strong hold as it has less boilerplate. When using script setup, simply importing the component is enough.

<script setup>
import Header from "./components/Header.vue";
</script>