Improve error reporting and logging

I had wrong imports of functions and wanted to use them in take(invalidMethod) and all I got was a mysterious invalid type error in the console. I did not know which saga it originated from. I understand that redux-saga cannot know where it comes from.

Therefore I am thinking maybe we can extend the saga steps with optional comments, that will help to improve error reporting.

yield log(take(WAIT_FOR_ACTION), "Waiting for action")
yield log(call(asyncFunc, withParams), "Calling async function")
yield log(put(SET_RESULT_ACTION), "Setting the result of the async call")

It would not break the existing API What you think?

Proposed implementation:

function *log(func, message) {
  console.log(message)
  yield func
}

[bolismauro]

I’m not sure if this is related to this issue but I’ve just started to work with sagas and I find almost impossible to debug saga code. The main issues I have are:

• breakpoints basically don’t work (either they are not triggered, or functions like ‘next step’ behave in a weird way
• when there is an exception inside a saga (or a function invoked using call inside a saga) nor the stack trace or the error message is meaningful

I’m using the latest version of Chrome but I’ve also tried Safari and Chrome. Most likely these issues are not directly related to redux-saga but I wonder if there is a way to support developers in the debugging process because right now I think it is really really hard

[yelouafi]

@pke I think you can implement the log utility without involving the core. put, take, … are simple pure functions which return plain objects so you can just wrap them in whatever you want

function log(effect, message) {
  console.log(message)
  return effect
}

function* saga() {
  // will log then return the result of take
  yield log(take(WAIT_FOR_ACTION), "Waiting for action")
}