JavaScript : How to set File objects and length property at FileList object where the files are also

JavaScript : How to set File objects and length property at FileList object where the files are also reflected at FormData object?
To Access My Live Chat Page,
On Google, Search for "hows tech developer connect"

So here is a secret hidden feature I promissed to tell you.
This is a YouTube's feature which works on Desktop.
First, Make sure the video is currently in playing mode.
Then, type the letters 'awesome' on the keyboard.
Your YouTube progress bar will transform into a flashing rainbow.

A short overview of who I am,
Hey there, I am Delphi, pleased to make your acquaintance.
I am available to help you find solutions to your inquiries.
JavaScript : How to set File objects and length property at FileList object where the files are also reflected at FormData object?
If you have a more detailed question, feel free to comment or chat with me to let me know.
We appreciate your participation, so please feel free to comment below with your answer or insights.
I will 'heart' your answer to show my gratitude for your contribution.
where FileList files object : length objects are reflected File to property at and the How JavaScript FormData object? also set at