To find index of all occurrences of element in array, we use the map and filter method.
For instance, we write
const nanoIndexes = cars
.map((car, i) => (car === "Nano" ? i : -1))
.filter((index) => index !== -1);
to call map with a callback that checks if the car value being iterated through is 'Nano'.
If it is, we return i and we return -1 otherwise.
Then we call filter with a callback that returns an array with the index value not equal to -1.
