Answer 1

Or use array method, map

const fruits2 = fruits.map(fruit => fruit ? fruit : "new fruit");

Answer 2

reduce()

reduce() loops through original array,
and then returns a "result" (Not necessarily an array).

reduce() accepts two parameters:
1. A reducer function
2. Initial Value

For the reducer function, it accepts two to four parameter:
1. Accumulator
2. Each item of original array
3. (Optional) Index of the item in original array
4. (Optional) Original Array

Demo:

https://code.sololearn.com/cqHxL5WFU1PQ/?ref=app

Ref:

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/reduce