How to Build Fair Timing Judgement Windows for Browser Rhythm Games in JS

A common source of unfairness in rhythm games is flawed timing logic that blends animation frames, wall-clock time, and audio playback position. The fix is to use a single authoritative clock — specifically the Web Audio API's currentTime — to drive both note positions and input judgement. Judgement windows should be defined as explicit, tunable data structures, with each input calibrated at the boundary to account for player-specific latency tendencies. Notes must be resolved only once to prevent duplicate scoring from keyboard repeat events or simultaneous listeners. Keeping audio timing, note selection, calibration, and scoring as separate concerns makes the system predictable and straightforward to test.