Inconsistent Error Handling Across Browsers for Network Failures

[nycruslan]

Description: There is an inconsistency in how the i18next-http-backend plugin handles network errors across different browsers. The current implementation checks for specific error messages to determine whether to retry a failed request. However, different browsers return different error messages, leading to inconsistent behavior.

Steps to Reproduce:

1. Use the i18next-http-backend plugin in a project.
2. Simulate a network failure (e.g., by disconnecting from the internet or blocking the request).
3. Observe the error messages in different browsers:
   • Chrome: "Failed to fetch"
   • Firefox: "NetworkError when attempting to fetch resource."
   • Safari: "Load failed"

Expected Behavior: The plugin should consistently identify network-related errors and decide whether to retry the request, regardless of the browser being used.

Actual Behavior: The plugin's error handling logic is inconsistent due to different error messages returned by various browsers.

Proposed Solution: Modify the error-checking logic to account for the different error messages across browsers. Here is a suggested revision:

if (!res && err && err.message) {
  const errorMessage = err.message.toLowerCase();
  const isNetworkError = errorMessage.includes('failed') || errorMessage.includes('fetch') || errorMessage.includes('network') || errorMessage.includes('load');
  if (isNetworkError) {
    return callback('failed loading ' + url + ': ' + err.message, true /* retry */);
  }
}

Reference to the code: https://github.com/i18next/i18next-http-backend/blob/master/lib/index.js#L77

Environment:

• i18next-http-backend version: 2.6.1
• Browser: Chrome, Firefox, Safari
• Operating System: MacOS

Additional Context: This issue affects the reliability of the plugin in handling network errors, which can impact the user experience by either failing to retry requests when appropriate or retrying unnecessarily.

[adrai]

Can you please provide a PR?

[adrai]

Thank you @nycruslan

[nycruslan]

Thank you @nycruslan

Thank you for quick reply.