Parse Query Aggregate 'group' error when 'objectId' is not a string

[thodinh]

Issue Description

I wanna stats users that register by day, so I use the aggregate query to count. Code here:

Parse.Cloud.define('statsUserByCreatedDate', (req, res) => {
    var pipeline = [{
        group: { 
            objectId: { day: { $dayOfMonth: "$_created_at" }, month: { $month: "$_created_at" }, year: { $year: "$_created_at" } }, 
            count: { $sum: 1 } }
        }
    ];
    var query = new Parse.Query(Parse.User);
    query.aggregate(pipeline, { useMasterKey: true })
        .then(function(results) {
            res.success(results);
        })
        .catch(function(error) {
            res.error(error)
        });
});

But, I get the error:

Error generating response. TypeError: stage.$group._id.substring is not a function
at __dirname.aggregate.pipeline.map.stage (<project_dir>/node_modules/parse-server/lib/Adapters/Storage/Mongo/MongoStorageAdapter.js:493:42)
    at Array.map (native)
    at MongoStorageAdapter.aggregate (<project_dir>/node_modules/parse-server/lib/Adapters/Storage/Mongo/MongoStorageAdapter.js:490:25)
    at __dirname.find.query.loadSchema.then.schemaController.getOneSchema.catch.then.schema.then.then.then (<project_dir>/node_modules/parse-server/lib/Controllers/DatabaseController.js:912:35)
    at process._tickDomainCallback (internal/process/next_tick.js:135:7)
...

This is the code occurs error

MongoStorageAdapter.js

aggregate(className, schema, pipeline, readPreference) {
    let isPointerField = false;
    pipeline = pipeline.map(stage => {
      if (stage.$group && stage.$group._id) {
          const field = stage.$group._id.substring(1);
          if (schema.fields[field] && schema.fields[field].type === 'Pointer') {
            isPointerField = true;
            stage.$group._id = `$_p_${field}`;
          }
      }
...

In my case above I tried check typeof stage.$group._id (if (typeof stage.$group._id === 'string')) and it works to me. But I don't know how in any other case.

Please check it!

Thanks

Environment Setup

• Server
  • parse-server version: 2.7.2