TypeScript is not reporting errors from vueCompilerOptions.checkUnknownEvents

[johannes-lindgren]

Vue - Official extension or vue-tsc version

vue-tsc@2.2.8

VSCode version

Vue version

vue@3.5.13

TypeScript version

typescript@5.7.3

System Info

System:
    OS: macOS 15.1
    CPU: (8) arm64 Apple M1 Pro
    Memory: 86.48 MB / 16.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 22.9.0 - ~/.nvm/versions/node/v22.9.0/bin/node
    Yarn: 1.22.22 - ~/.asdf/shims/yarn
    npm: 10.9.0 - ~/.nvm/versions/node/v22.9.0/bin/npm
    pnpm: 9.14.4 - ~/.nvm/versions/node/v22.9.0/bin/pnpm
  Browsers:
    Brave Browser: 134.1.76.73
    Chrome: 134.0.6998.89
    Safari: 18.1

package.json dependencies

{
  "dependencies": {
    "vue": "^3.5.13"
  },
  "devDependencies": {
    "@vitejs/plugin-vue": "^5.2.1",
    "@vue/tsconfig": "^0.7.0",
    "typescript": "~5.7.2",
    "vite": "^6.2.0",
    "vue-tsc": "^2.2.4"
  }
}

Steps to reproduce

1. Initialize a new vite project with vue and TypeScript

pnpm create vite my-vue-app-2 --template vue-ts

2. Add vueCompilerOptions.strictTemplates: true to tsconfig.app.json

{
  "vueCompilerOptions": {
    "strictTemplates": true,
  },
}

3. Open src/App.vue
4. In <HelloWorld />, add an unknown emit handler. For reference, also add an unknown prop.

<template>
  <HelloWorld 
      msg="Vite + Vue"
      thispropdoesnotexist="sfsdf"
      @thisemitdoesnotexist="() => {}"
  />
</template>

Run vue-tsc:

~/workspaces/tmp/vite-project
vue-tsc -b
src/App.vue:8:7 - error TS2353: Object literal may only specify known properties, and 'thispropdoesnotexist' does not exist in type '{ readonly msg: string; } & VNodeProps & AllowedComponentProps & ComponentCustomProps'.

8       thispropdoesnotexist="sfsdf"
        ~~~~~~~~~~~~~~~~~~~~


Found 1 error.

It finds the error for the unknown prop, but not the unknown event.

You can also try adding vueCompilerOptions.checkUnknownEvents: true

What is expected?

According to the docs, checkUnknownEvents and strictTemplates should:

Check unknown props.

I interpret this as it should check emits—the same way it checks props.

What is actually happening?

There is seemingly no type checking on unknown props

Link to minimal reproduction

No response

Any additional comments?

No response

[KazariEX]

It has been fixed at v3.0.