systematic-debugging

Follow the four phases: investigate the root cause by reading errors and reproducing consistently, analyze patterns against working examples, form and test a single hypothesis, then implement one fix with a failing test case. Never propose fixes before completing the investigation phase.

Trace backward through the call chain from the immediate cause to the original trigger, asking what called each level and what value was passed. Add stack trace instrumentation with console.error before the failing operation, and fix at the source rather than where the error appears.

Replace arbitrary setTimeout or sleep delays with condition-based waiting that polls for the actual condition you need, such as an event appearing or state changing. Poll every 10ms with a timeout, and only use fixed delays when testing documented timing behavior.

Stop after three failed fixes and question the architecture rather than attempting a fourth. Repeated failures where each fix reveals new problems elsewhere indicate a fundamentally wrong pattern, so discuss refactoring with your team instead of continuing to patch symptoms.

Never, according to this methodology. Even under production emergencies or time pressure, systematic investigation is faster than guess-and-check thrashing, and symptom fixes are treated as failures that create rework and new bugs.