[Bug] Async function declaration

[kobezzza]

eslint 3.1.1
"parser": "babel-eslint"

export async function main() {

}

Output:

Cannot read property 'value' of undefined
TypeError: Cannot read property 'value' of undefined
    at getStarToken (C:\Users\kobez\Documents\dev\TravelChat\node_modules\eslint\lib\rules\generator-star-spacing.js:68:25)
    at EventEmitter.checkFunction (C:\Users\kobez\Documents\dev\TravelChat\node_modules\eslint\lib\rules\generator-star-spacing.js:123:29)
    at emitOne (events.js:101:20)
    at EventEmitter.emit (events.js:188:7)
    at NodeEventGenerator.enterNode (C:\Users\kobez\Documents\dev\TravelChat\node_modules\eslint\lib\util\node-event-generator.js:40:22)
    at CodePathAnalyzer.enterNode (C:\Users\kobez\Documents\dev\TravelChat\node_modules\eslint\lib\code-path-analysis\code-path-analyzer.js:607:23)
    at CommentEventGenerator.enterNode (C:\Users\kobez\Documents\dev\TravelChat\node_modules\eslint\lib\util\comment-event-generator.js:97:23)
    at Controller.traverser.traverse.enter (C:\Users\kobez\Documents\dev\TravelChat\node_modules\eslint\lib\eslint.js:902:36)
    at Controller.__execute (C:\Users\kobez\Documents\dev\TravelChat\node_modules\eslint\node_modules\estraverse\estraverse.js:397:31)
    at Controller.traverse (C:\Users\kobez\Documents\dev\TravelChat\node_modules\eslint\node_modules\estraverse\estraverse.js:501:28)

Process finished with exit code 1

With

export const main = async () => {

};

All fine.

[mysticatea]

Thank you for this issue.

Async functions are not a part of JavaScript yet (it's a proposal).
You can use babel-eslint and eslint-plugin-babel in order to use such features.

Especially, you can use babel/generator-star-spacing rule for that error.

[kobezzza]

@mysticatea i always use babel-eslint, and ESlint crashes. Toggle off generator-star-spacing fixed it, thanks.

[adiachenko]

@mysticatea Async functions proposal has been moved to stage 4. I don't know if I'm correct but I seem to have read somewhere that you may support stage 4 proposals.

[mysticatea]

@adiachenko It happened after this issue. 😄

Now we are working for supports of the new stage 4 features.
We need several steps.

1. Acorn, the base of our parser, supports those: Work on ECMAScript 2017? acornjs/acorn#441
2. Our parser supports those: async function and await expression! espree#287
3. Then, ESLint rules support those.
   Actually, wrong AST nodes of babel-eslint cause the error, I think. So we cannot fix rules before our parser supports those.

[hzoo]

@mysticatea babel/babel-eslint#350