Add support for ESlint 8.0 in `vue-eslint-parser`

Version

Vue CLI:  4.5.14

Environment info

Node version: v14.17.0
npm version: 6.14.13
Local ESLint version: 8.0.1
Operating System: macOS Big Sur

What did you do?

I’m using Vue CLI & after upgrading ESlint from version 7.32.0 to 8.0.1 I get the error Syntax Error: TypeError: eslint.CLIEngine is not a constructor after launching the project for development with npm run serve.

// .eslintrc.js
module.exports = {
  root: true,
  env: {
    node: true
  },
  extends: ["plugin:vue/essential", "@vue/prettier"],
  rules: {
    "no-console": process.env.NODE_ENV === "production" ? "error" : "off",
    "no-debugger": process.env.NODE_ENV === "production" ? "error" : "off"
  },
  parserOptions: {
    parser: "babel-eslint"
  }
};

Steps to reproduce

• Install Vue CLI globally, run the command: npm install -g @vue/cli.
• Create a project, run the command vue create todo-list-vue.
• Navigate to the project & install the latest version of ESlint, run the command cd todo-list-vue && npm install eslint@latest.
• Launch the project for development, run the command npm run serve.

You will get the following error in the console: Syntax Error: TypeError: eslint.CLIEngine is not a constructor

What is expected?

Before upgrading ESlint, I was able to launch the project for development without issues.

What is actually happening?

I got this error: Syntax Error: TypeError: eslint.CLIEngine is not a constructor & my code won’t compile for development.

Related link

Bug: TypeError: this.cliEngine is not a constructor

[naregkhodanian]

Can’t believe this issue is still happening

[Morl99]

This is already fixed in https://github.com/vuejs/vue-cli/pull/6714 so a backport to the v4 line would be necessary. I think it would be great to support eslint 8 in vue-cli 4.x, since it will take people a while even after the v5 release to migrate their projects, and it would be problematic, to be stuck with eslint 7 in that case.