github-dedupe-viewed-files.js

viewedFiles.forEach(viewedFile => {
 const currentFile = document.querySelectorAll(`div[data-path="${viewedFile.path}"]`)[0] || undefined;
 if(currentFile) {
   let currentDiffstat = currentFile.querySelectorAll("span.diffstat")[0].getAttribute('aria-label');
   let match = viewedFile.diffstats === currentDiffstat;
   console.log(`match: ${match} - ${viewedFile.path} - viewedDiffstat: ${viewedFile.diffstats}, currentDiffstat: ${currentDiffstat}`);

   if(match) {
     let checkbox = currentFile.querySelectorAll('input[type="checkbox"]')[0];
     let viewed = checkbox.checked || false;
     
     if(!viewed) {
       checkbox.click();
       console.log('changed to viewed!');
     } else {
       console.log('already is viewed!');
     }
   }
 } else {
   console.log(`match: skipped - ${viewedFile.path}`);
 }
});

github-diff-headers.js

const diffHeaders = [...document.querySelectorAll("div.file-header")].map(node => ( 
   { 
       path: node.attributes['data-path'].value, 
       diffstats: node.querySelectorAll("span.diffstat")[0].getAttribute('aria-label')
   })
);

github-transfer-data-between-tabs.js

//run the diff-headers script to dump the list of viewed files into an array
//perform the actions stated here to transfer the data to another open PR
//run the dedupe script to mark as 'viewed' all the files that have matching pathnames + diffstats

JSON.stringify(diffHeaders);

switch tab ->

const diffHeaders = ... ctrl+v to paste the raw json, delete the outer most quotes and surround by ``
const viewedFiles = JSON.parse(diffHeaders);