Javascript Object creation from two array

Suppose I have two array:

days = [3, 5, 7, 9]
values = [[13, 15, 17, 19], [14, 16, 18, 20]]

What I want is create another 2 dimensional array with the following manner:

1. Say I choose day = 5
2. Create an array as [[15, 15, 15, 15], [16, 16, 16, 16]]

What I am doing here is for day = 5, the 1st array has value 15, so the created array will have the 1st array filled with 15 and for the second array (similarly) with 16.

In python this would be easy:

days = [3, 5, 7, 9]
values = [[13, 15, 17, 19], [14, 16, 18, 20]]
day_index = days.index(5)
res = [[i[day_index]] * len(i) for i in values]

How to accomplish that in javascript? I can get the index with indexOf, but having trouble with the second part.

>Solution :

Try this one

const days = [3, 5, 7, 9];
const values = [[13, 15, 17, 19], [14, 16, 18, 20]];
const dayIndex = days.indexOf(5);
const res = values.map(arr => Array(arr.length).fill(arr[dayIndex]));