boat_lines_logic.js

// You grab this data from the page
let hours = [5, 6, 7, 8]
let minutes = [
    [15, 15, 05, 05],
    [45, 35, 15, 15],
    [null, 45, 25, 25],
    [null, 55, 45, 30],
    [null, null, 40, 40],
    [null, null, 50, 45],
    [null, null, 55, 55],
]

// The object
let calendar = {}

// Logic 🛠️
hours.forEach((item, column) => {
        calendar[item] = [];

        minutes.forEach(row => {
            calendar[item].push(row[column])
        })
})


/*
That should be the result

> calendar
{ '5': [ 15, 45, null, null, null, null, null ],
  '6': [ 15, 35, 45, 55, null, null, null ],
  '7': [ 5, 15, 25, 45, 40, 50, 55 ],
  '8': [ 5, 15, 25, 30, 40, 45, 55 ] }
*/

Scraper.js

const got = require('got');
const { JSDOM } = require('jsdom');

(async () => {
    const { body } = await got("https://ttsl.pt/passageiros/horarios-de-ligacoes-fluviais/ligacao-barreiro-terreiro-do-paco/");

    const { window: { document } } = new JSDOM(body);

    const [t1, t2] = Array.from(document.getElementById('Dias úteis').children)
        .filter(element => element.classList.contains('table-responsive'))
        .map(tableContainer => {
            const item = Array.from(tableContainer.children[0].children);

            return { thead: item[0], tbody: item[1] }
        })
    
    const hours = { t1: {}, t2: {} }
    const T1Hours = Array.from(t1.thead.children[0].children).map(item => item.innerHTML)
    const T1Minutes = Array.from(t1.tbody.children).map(item => Array.from(item.children).map(item => {
        let content = item.innerHTML;
        return content.trim() !== '' ? content.replace(/\D/g, '') : null
    }))

    const T2Hours = Array.from(t2.thead.children[0].children).map(item => item.innerHTML)
    const T2Minutes = Array.from(t2.tbody.children).map(item => Array.from(item.children).map(item => {
        let content = item.innerHTML;
        return content.trim() !== '' ? content.replace(/\D/g, '') : null
    }))

    T1Hours.forEach((item, column) => {
        hours.t1[item] = [];

        T1Minutes.forEach(row => {
            hours.t1[item].push(row[column])
        })
    })

    T2Hours.forEach((item, column) => {
        hours.t2[item] = [];

        T2Minutes.forEach(row => {
            hours.t2[item].push(row[column])
        })
    })
})()