Time-based jumping & double-jumping

Hi everyone. I am working getting these two features working in our game and I started to use this method for time-based jump and this method for double jumping, but the two implementations interfere with each other.

What I mean is that the time-based jumping depends on the player holding down the jump button, resulting in repeated calls to jump(), which in turn adds, to the player's Y velocity until the max time is reached. While the double jump logic depends on the player pressing jump a second time while the player is in the air.

Now, I had thought that I could possibly wait for the player to complete the apex of the original jump before allowing the second jump to occur, but I am not quite sure how to implement this with the PSK framework.

What I am looking for is a good solution to accomodate both functions, or possibly to work it out with the community on this thread. Any help is appreciated.