When attempting to export a generator function in order to use in a Redux-Saga, ES-Lint is telling me that I have an error in my code:
[eslint] Expected a function declaration. (func-style)
It exports just fine the way that it is currently, and the rule is currently being ignored:
/*eslint-disable func-style*/
const myExampleSaga = function* () {
yield takeEvery('DO_SOMETHING_REQUEST', andDoThisFunc);
};
export default myExampleSaga;
I am more or less okay with the fact that ES-Lint does not support generators (or at least it would seem that way), however I would like to know why the following code does not work:
export default function* () {
yield takeEvery('DO_SOMETHING_REQUEST', andDoThisFunc);
}
With the following error message:
undefined is not an object (evaluating 'regeneratorRuntime.mark')
The error message is being thrown from my rootSaga, which looks like this:
/*eslint-disable func-style*/
export const rootSaga = function* rootSaga() {
yield all([
spawn(myExampleSaga)
]);
};
Can anyone tell me why the above code is invalid? I think it has something to do with hoisting, however I was not able to find any reason why that would be invalid.
This is well-known issue of
regenerator-transform
babel plugin, which is commonly used for transpiling code with sagas. That issue also affectsasync
functions, because they are implemented byregenerator-transform
mechanism too.After transforming that code , there can be two issues. First is omitting inclusion of
regenerator-runtime
dependency, which is mandatory. Second is function hoisting, so if occurrence order matters, it should be specified implicitly.Correct solution is: