Delete orphaned Chunks from Mongo GridFs

delete-chunks.js

db.getCollection('fs.chunks').aggregate([
  { $lookup: { from: 'fs.files', localField: 'files_id', foreignField: '_id', as: 'file' } },
  { $unwind: { path:'$file', preserveNullAndEmptyArrays: true } },
  { $match: { file: { $exists: false } } },
  { $project: { _id: 1, files_id: 1 } },
]).forEach(function(chunk) {
  printjson(chunk);  
  // db.getCollection('fs.chunks').remove({ _id: chunk._id });
});