Scrapes IVLE for module CourseIDs

ivle-scraper.user.js

// ==UserScript==
// @name        Scrapes IVLE Course ID 
// @namespace   yijiang
// @version     1
// @match       https://ivle.nus.edu.sg/v1/lms/list_course.aspx?src=bm&code=&title=&lecName=&acadyear=2016%2f2017&semester=Semester+1&ModTitleExact=N&LecNameExact=N
// @grant       none
// ==/UserScript==

function switchPage(page){
    $('#GV_Page2').val(page).change(); 
}   


function getCourseId(url){ 
    let query = url.split('?')[1]; 
    let queryParts = query.split('&'); 
    for (let i = 0; i < queryParts.length; i++) {
        let [key, value] = queryParts[i].split('='); 
        if (key === 'CourseID') return value; 
    }
}

function scrapePage(){
    let timeBetweenPage = 10 * 1000; // 5 seconds  
    let codes = JSON.parse(localStorage.getItem('course-code-id') || '{}'); 
    let lastScrapedPage = +localStorage.getItem('last-scraped') || 0; 

    let currentPage = +$('#GV_Page2').val(); 

    if (currentPage != lastScrapedPage+1)
        switchPage(lastScrapedPage+1); 


    $('a[href^="/V1/Module/Student/default.aspx?CourseID="]').each((i, e) => {
        let courseId = getCourseId(e.href); 
        if (courseId) {
            codes[e.textContent.trim()] = courseId; 
        } else {
            console.error(e.textContent.trim() + ' has no course ID'); 
        }
    });

    localStorage.setItem('course-code-id', JSON.stringify(codes));
    localStorage.setItem('last-scraped', currentPage);
    
    setTimeout(() => switchPage(lastScrapedPage+1), timeBetweenPage); 
}

setTimeout(scrapePage, 10 * 1000);