If set, determines how many cycles. By default unlimited. Use 1 for example for a one-shot wave.
Starting absolute value of source.
Starting relative value of source (eg 0.5 for 50%)
Function that returns current time in milliseconds. Defaults to performance.now. Useful for testing.
performance.now
If set, determines how many cycles. By default unlimited. Use 1 for example for a one-shot wave.