pixiv-follows.js

const pixivFollows = (async function (userId, private) {
  const initialCheck = await fetch(`https://www.pixiv.net/ajax/user/${userId}/following?offset=0&limit=1&rest=${private ? 'hide' : 'show'}&lang=en`);
  const initialJson = await initialCheck.json();
  const total = initialJson.body.total;
  let users = [];
  const numPerGet = 100;
  console.log(`total private following ${total}`)

  for(let i = 0; i < total; i += numPerGet) {
    console.log(`getting follows ${i} to ${Math.min(i + numPerGet, total)}`);
    const newCheck = await fetch(`https://www.pixiv.net/ajax/user/${userId}/following?offset=${i}&limit=${numPerGet}&rest=${private ? 'hide' : 'show'}&lang=en`);
    const newJson = await newCheck.json();
    const newUsers = newJson.body.users.map(({userId, userName}) => ({userId, userName}));
    console.log(`found ${newUsers.length} users`);
    users = users.concat(newUsers);
  }
  console.log(`got ${users.length} users total`);
  console.log(users);
  
  let dataStr = 'data:text/json;charset=utf-8,' + encodeURIComponent(JSON.stringify(users, null, 2));
  let downloadAnchorNode = document.createElement('a');
  downloadAnchorNode.setAttribute('href', dataStr);
  downloadAnchorNode.setAttribute('download', `pixiv-follows-${private ? 'private' : 'public'}-${userId}.json`);
  downloadAnchorNode.click();
  downloadAnchorNode.remove();
})