v2 -> v3 data migration test scripts

extract.js

// NUSMods v2 timetable data extractor

var loaderTemplate = data => `
var s = document.createElement('script');
s.src = 'https://cdnjs.cloudflare.com/ajax/libs/localforage/1.5.5/localforage.min.js';

s.onload = function() {
  const data = ${data};
  let count = 0;

  data.forEach(([key, queryString]) => {
    localforage
      .setItem(key, queryString)
      .then(() => {
        count++;

        if (count === data.length) {
          localStorage.clear();
          window.location.reload();
        }
      });
  });
};

document.body.append(s);`;

var s = document.createElement('script');
s.src = 'https://cdnjs.cloudflare.com/ajax/libs/localforage/1.5.5/localforage.min.js';
s.onload = function() {
    const keys = [
        'timetable/2017-2018/sem1:queryString', 
        'timetable/2017-2018/sem2:queryString',
        'timetable/2017-2018/sem3:queryString',
        'timetable/2017-2018/sem4:queryString',
    ];
    const data = [];

    keys.forEach(key => localforage.getItem(key)
        .then(queryString => {
            data.push([key, queryString]);

            if (data.length === keys.length) {
                const stringified = JSON.stringify(data, null, 2);
                console.log('Data extracted! Go to https://deploy-preview-518--nusmods.netlify.com/ and paste the code below into the console');
                console.log(loaderTemplate(stringified));
            }
        }))
};

document.body.append(s);

To use:

1. Run the extractor.js code in the browser console (Ctrl + Shift + J) on https://nusmods.com/
2. Copy the outputted code from the console
3. Go to https://deploy-preview-518--nusmods.netlify.com/ and paste the code into the console there. The page will reload after the v2 data have been saved.
4. Verify that the the timetable has been migrated successfully for all four semesters. This means that
   • The modules match
   • The position of lessons match
   • localStorage should have an extra v2Migration key that indicates the migration has been completed successfully

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