Using asynchronous import statements in Vue allows for more efficient loading of components

Question

Using asynchronous import statements in Vue allows for more efficient loading of components

I am using Vue and have a method in my file called load.js.

async function loadTask(x) {
  return await x; // Some async code
}

export { loadTask };

In one of my Vue components, I call the method but encounter an issue where the use of await prevents the <template> from loading. When I remove the await, the code below executes successfully. Can you help me understand what I might be missing?

<script setup>
import { loadTask } from './methods/load.js';
const test = loadTask(3);
console.log(await test);
</script>
<template>
  <div>This section does not render properly.</div>
</template>

javascript vue.js import async-await export

Answer 1

Answer №1

After consulting the official documentation:

async setup() should be utilized in conjunction with Suspense, which is still considered an experimental feature at this time. The intention is to finalize and provide detailed documentation on it in a forthcoming release - however, if you're keen to learn more now, you can review its tests to gain insights on how it functions.

https://v3.vuejs.org/api/sfc-script-setup.html#top-level-await

https://v3-migration.vuejs.org/breaking-changes/suspense.html#suspense

Vue <script setup> Top level await causing template not to render

Therefore, if you employ async setup, ensure that you import this component in the parent component as follows:

import { defineAsyncComponent } from "vue";

export default {
  components: {
    HelloWorld: defineAsyncComponent(() =>
      import("./components/HelloWorld.vue")
    ),
  },
};
</script>

Then, use it within the template enclosed in suspense tags:

<template>
  <suspense>
    <template #default>
      <HelloWorld />
    </template>
    <template #fallback>
      <div>Loading...</div>
    </template>
  </suspense>
</template>

Demo:

https://codesandbox.io/s/reverent-sinoussi-9r5or?file=/src/components/HelloWorld.vue

Answer 2

After consulting the official documentation:

async setup() should be utilized in conjunction with Suspense, which is still considered an experimental feature at this time. The intention is to finalize and provide detailed documentation on it in a forthcoming release - however, if you're keen to learn more now, you can review its tests to gain insights on how it functions.

https://v3.vuejs.org/api/sfc-script-setup.html#top-level-await

https://v3-migration.vuejs.org/breaking-changes/suspense.html#suspense

Vue <script setup> Top level await causing template not to render

Therefore, if you employ async setup, ensure that you import this component in the parent component as follows:

import { defineAsyncComponent } from "vue";

export default {
  components: {
    HelloWorld: defineAsyncComponent(() =>
      import("./components/HelloWorld.vue")
    ),
  },
};
</script>

Then, use it within the template enclosed in suspense tags:

<template>
  <suspense>
    <template #default>
      <HelloWorld />
    </template>
    <template #fallback>
      <div>Loading...</div>
    </template>
  </suspense>
</template>

Demo:

https://codesandbox.io/s/reverent-sinoussi-9r5or?file=/src/components/HelloWorld.vue

Answer 3

Answer №2

As explained in this Stackoverflow post, if you don't require the full capabilities of async components and Suspense, there are alternative approaches such as using onBeforeMount:

const example = ref('');
onBeforeMount(async () => {
  example.value = await loadTask(3);
  console.log(example.value);
})

Another option is to initialize within an async function that doesn't wait for the promise to complete:

const example = ref('');
const init = async () => {
  example.value = await loadTask(3);
  console.log(example.value);
}
init();

Alternatively, you can use promise chaining:

const example = ref('');
loadTask(3).then(task => {
  example.value = task;
  console.log(example.value);
});

It's important to also handle errors appropriately based on each method.

Answer 4

As explained in this Stackoverflow post, if you don't require the full capabilities of async components and Suspense, there are alternative approaches such as using onBeforeMount:

const example = ref('');
onBeforeMount(async () => {
  example.value = await loadTask(3);
  console.log(example.value);
})

Another option is to initialize within an async function that doesn't wait for the promise to complete:

const example = ref('');
const init = async () => {
  example.value = await loadTask(3);
  console.log(example.value);
}
init();

Alternatively, you can use promise chaining:

const example = ref('');
loadTask(3).then(task => {
  example.value = task;
  console.log(example.value);
});

It's important to also handle errors appropriately based on each method.

Using asynchronous import statements in Vue allows for more efficient loading of components

Answer №1

Answer №2

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