The read-only context property of the AudioNode interface returns the associated BaseAudioContext, that is the object representing the processing graph the node is participating in.
The AudioContext or OfflineAudioContext object that was used to construct this AudioNode.
const audioCtx = new AudioContext();
const oscillator = audioCtx.createOscillator();
const gainNode = audioCtx.createGain();
oscillator.connect(gainNode).connect(audioCtx.destination);
console.log(oscillator.context); // AudioContext
console.log(oscillator.context === audioCtx); // true