AngularJS $http Timeout: Diagnosing Unexpected Status -1 Errors

Goal

Determine why an AngularJS 1.x application’s $http requests are failing with a status of -1 and a statusText of "timeout" even though the server should respond within the configured timeframe.

Constraints & Uncertainty

• The $http service is configured with a numeric timeout in milliseconds, but the actual request duration may vary across browsers and network conditions.
• Server‑side processing time is unknown; the client aborts after the timeout regardless of server completion.
• Network errors can masquerade as timeouts in some environments, complicating error source identification.

Specific Questions

1. What mechanisms does AngularJS use internally to trigger and reject the promise when the timeout expires?
2. How can one programmatically distinguish a client‑side timeout from a network failure or server‑side timeout when inspecting the error object?
3. What best‑practice patterns exist to adjust the timeout dynamically based on the request type or current network latency?