Improve error handling

[ShGKme]

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1. Do not use console.debug for errors, use console.error if necessary

We also use console.info and console.warn sometimes. Shouldn't we use console.debug only for debugging related stuff?

Why: Errors should be logged as errors, they have a separate place in the dev tools and display

Examples:

try {
  await foo()
} catch (error) {
  // ❌
  console.debug(error)
  // ✅
  console.error(error)
}

2. Do not catch an exception, if it is not required

Catch an exception in case:

1. You need special processing
2. An exception here may break something

Why: a caught exception is "missed" from further processing

Examples:

try {
  await foo()
} catch(error) {
  // ❌ Catch just in case
  console.error(error)
}

try {
  await foo()
} catch(error) {
  // ✅ Some special processing, for example
  // ...showing a toast
  showError(error.message)
  // ...work with the exception
  if (error.responsestatusCode === 404) {
    // Special case
  }
}

// 📁 someStore.js
const actions = {
  someAction({ commit }) {
    try {
      commit('FOO')
      await foo()
    } catch(error) {
      // ✅ Need to revert changes
      commit('REVERT_FOO')
      }
    }
  }
}

// 📁 Component.vue
export default {
  async created() {
    try {
      await foo()
    } catch(error) {
      // ✅ The component mounting will be failed without catching the error
      // Some processing
    }
  },
}

3. Don't forget to re-throw an exception if it may not be processed

Why: Otherwise it is missed

Example:

try {
  await foo()
} catch(error) {
  if (error.responsestatusCode === 418) {
    // ...Custom processing...
  } else {
    // ✅
    // What if the error is not 418 ?
    throw error
  }
}

4. Think about possible exceptions and errors

try {
  await foo()
} catch(error) {
  // What may go wrong in `foo`?
  // Only general unexpected exceptions? Or also some domain-level errors?
  // May there be special results of `foo` that we need to proceed implicitly?
}

5. General errors

In case an error required special processing (for example, displaying a special message) and it is some specific action error, some general app-wide error - add general catching.

For example:

• axios interception
• Top-level window.addEventListener('error') or app level catch
• Top-level window.addEventListener('unhandledPromiseRejection') or app level catch

See also

• https://github.com/goldbergyoni/nodebestpractices#2-error-handling-practices