When `@vitejs/plugin-vue` compiles the `<template>` blocks in SFCs, it also converts any encountered asset URLs into ESM imports.
For example, the following template snippet:
```vue
<imgsrc="../image.png"/>
```
Is the same as:
```vue
<scriptsetup>
import _imports_0 from '../image.png'
</script>
<img:src="_imports_0"/>
```
By default the following tag/attribute combinations are transformed, and can be configured using the `template.transformAssetUrls` option.
```js
{
video: ['src', 'poster'],
source: ['src'],
img: ['src'],
image: ['xlink:href', 'href'],
use: ['xlink:href', 'href']
}
```
Note that only attribute values that are static strings are transformed. Otherwise, you'd need to import the asset manually, e.g. `import imgUrl from '../image.png'`.
## Example for passing options to `vue/compiler-sfc`:
```ts
import vue from '@vitejs/plugin-vue'
export default {
plugins: [
vue({
template: {
compilerOptions: {
// ...
},
transformAssetUrls: {
// ...
},
},
}),
],
}
```
## Example for transforming custom blocks
```ts
import vue from '@vitejs/plugin-vue'
import yaml from 'js-yaml'
const vueI18nPlugin = {
name: 'vue-i18n',
transform(code, id) {
// if .vue file don't have <i18n> block, just return
if (!/vue&type=i18n/.test(id)) {
return
}
// parse yaml
if (/\.ya?ml$/.test(id)) {
code = JSON.stringify(yaml.load(code.trim()))
}
// mount the value on the i18n property of the component instance
return `export default Comp => {
Comp.i18n = ${code}
}`
},
}
export default {
plugins: [vue(), vueI18nPlugin],
}
```
Create a file named `Demo.vue`, add `lang="yaml"` to the `<i18n>` blocks, then you can use the syntax of `YAML`:
```vue
<template>Hello</template>
<i18nlang="yaml">
message: 'world'
fullWord: 'hello world'
</i18n>
```
`message` is mounted on the i18n property of the component instance, you can use like this:
Vue 3.2 introduces the `defineCustomElement` method, which works with SFCs. By default, `<style>` tags inside SFCs are extracted and merged into CSS files during build. However when shipping a library of custom elements, it may be desirable to inline the styles as JavaScript strings and inject them into the custom elements' shadow root instead.
Starting in 1.4.0, files ending with `*.ce.vue` will be compiled in "custom elements" mode: its `<style>` tags are compiled into inlined CSS strings and attached to the component as its `styles` property: