How to initialize player.fadeIn with a variable using Tone.JS?

Question

• My project is playing a piece of audio using tone js and i want to use player.fadeIn to fade the audio in from the beginning.

• my goal is to just have a variable to control the fade duration of the player.

• any help on this is greatly appreciated thanks :)

• The functionality was successful when hardcoding the value as written below. This would fade the audio in with a duration of 5 seconds.

  • player.fadeIn = 5;
    

• When I tried to use a variable to represent the fade duration as written below, I would get the following error.

  • player.fadeIn = fadeDuration
    

  • ERROR:

    Type 'number | undefined' is not assignable to type 'Time'.
      Type 'undefined' is not assignable to type 'Time'.
    

• and if i tried changing the type of fade duration variable to type 'Time' a similar error is presented.

  • ERROR:

    Type 'Time | undefined' is not assignable to type 'Time'.
      Type 'undefined' is not assignable to type 'Time'.