Enable Top Level Await

[mudgen]

Please describe what the rule should do:
Provide a setting or rule that enables top level await in code without an error or warning.

V8 now supports top level await: https://v8.dev/features/top-level-await

As a standard top level await is in stage 3: https://github.com/tc39/proposal-top-level-await

I am currently using deno which has top level await, so this new setting/rule would be very useful for me.

[mdjermanovic]

Hi @mudgen, thanks for the issue!

I assume you're getting parsing errors. ESLint's default parser will support this syntax if and when it reaches stage 4, per our policy about experimental features.

In the meantime, you can use babel-eslint parser.

[eslint-deprecated]

Unfortunately, it looks like there wasn't enough interest from the team
or community to implement this change. While we wish we'd be able to
accommodate everyone's requests, we do need to prioritize. We've found
that issues failing to reach accepted status after 21 days tend to
never be accepted, and as such, we close those issues.
This doesn't mean the idea isn't interesting or useful, just that it's
not something the team can commit to.

Thanks for contributing to ESLint and we appreciate your understanding.

[mjsalinger]

@mdjermanovic - We don't use babel, but node.js just added support for top-level await. What is the recommended course if we want to use this feature of node without using Babel?

[anikethsaha]

top level await is still in stage 3.

eslint supports stage 4 proposal.

[mdjermanovic]

@mjsalinger our default parser supports only stage 4 proposals. You could use babel-eslint as a parser for eslint. without using Babel to transpile the code.

[billinghamj]

Although it is still in stage 3, it has now shipped unflagged in Node and other common JS environments, so might be worth reconsidering

[boggddan]

@mdjermanovic - We don't use babel, but node.js just added support for top-level await. What is the recommended course if we want to use this feature of node without using Babel?

Hi, Could help me?
I install "@babel/eslint-parser" and "@babel/plugin-syntax-top-level-await", but VS Code write error: Parsing error: Cannot use keyword 'await' outside an async function

package.json

{
  "name": "test",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "type": "module",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "dependencies": {
    "fastify": "^3.4.1"
  },
  "devDependencies": {
    "@babel/core": "^7.11.6",
    "@babel/eslint-parser": "^7.11.5",
    "@babel/plugin-syntax-top-level-await": "^7.10.4",
    "eslint": "^7.9.0",
    "eslint-config-airbnb-base": "^14.2.0",
    "eslint-plugin-import": "^2.22.0",
    "eslint-plugin-node": "^11.1.0"
  }
}

.eslintrc.cjs

module.exports = {
  parserOptions: {
    ecmaVersion: 2021,
    sourceType: 'module',
    parser: "@babel/eslint-parser"
  }
};

babel.config.json

{
  "plugins": ["@babel/plugin-syntax-top-level-await"]
}

Thank's

[mdjermanovic]

Hi @boggddan!

parser should be at the top level, please try with this .eslintrc.cjs:

module.exports = {
  parser: "@babel/eslint-parser",
  parserOptions: {
    ecmaVersion: 2021,
    sourceType: 'module'
  }
};

[iwaduarte]

+1 for enabling top level await even if it is not stage 4. Not everything is black and white. We should not be too constrained to rules.

Also another option solution without using babel-parser would also be welcoming, like disabling this specific parse error ?

[pubmikeb]

The Top Level Await is now supported by the stable (RTM) version of Node.js (15.x) without any flags even at 3rd stage, so it would be great to adopt this rule without waiting another 7 months until this feature will be accepted by TC39.

Alternative solutions could be:

• to add annotation to silence this error
• to move Top Level Await from error to warning with the further explanation about the ESLint TC39 stages support policy
• do not raise this error if the JavaScript version in eslintrc.json is targeted to ES.Next

[ljharb]

(what is RTM?)

[pubmikeb]

(what is RTM?)

https://en.wikipedia.org/wiki/Software_release_life_cycle#RTM