You may need an additional loader to handle the result of these loaders.

[AlanCumberbatch]

INFO Starting development server...
98% after emitting CopyPlugin

ERROR Failed to compile with 1 error

error in ./src/App.vue?vue&type=template&id=7ba5bd90&ts=true

Module parse failed: Unexpected token (6:27)
File was processed with these loaders:

• ./node_modules/@vue/cli-service/node_modules/vue-loader-v16/dist/templateLoader.js
• ./node_modules/cache-loader/dist/cjs.js
• ./node_modules/@vue/cli-service/node_modules/vue-loader-v16/dist/index.js
  You may need an additional loader to handle the result of these loaders.
  | const _hoisted_2 = /#PURE/_createElementVNode("br", null, null, -1 /* HOISTED */)
  |

export function render(_ctx: any,_cache: any,$props: any,$setup: any,$data: any,$options: any) {
| return (_openBlock(), _createElementBlock(_Fragment, null, [
| _createElementVNode("video", {

@ ./src/App.vue?vue&type=template&id=7ba5bd90&ts=true 1:0-293 1:0-293
@ ./src/App.vue
@ ./src/main.js
@ multi (webpack)-dev-server/client?http://172.20.10.4:8080&sockPath=/sockjs-node (webpack)/hot/dev-server.js ./src/main.js

[yuanhua118]

Solution:
You can delete lang = "ts" in the following code；

<script lang="ts">
import { defineComponent, ref } from 'vue';
import { createFFmpeg, fetchFile } from '@ffmpeg/ffmpeg';

</script>