Check the element length to flag status boolean

I am assigning as default checked false in this return Object, see the code

return Object.assign(file, {
    temp_id: _.uniqueId(),
    checked: false,
})

I have an exception, in case it is my first file dropped i want checked: true,

I know that my first file dropped is when

const filePosition = files.length returns 0,

how can i apply this condition in my checked?

Answer

If I understand correctly, you want to updated checked to true if file.length === 0 and false and file.length !== 0

If that is correct, you can just do:

return Object.assign(file, {
    temp_id: _.uniqueId(),
    checked: files.length === 0,
})