get-collection-structure.js

var structureTypes = {
  type: 'type',
  typeCount: 'typeCount',
};

// ============ PARAMETERS =============
var collectionName = '';
var limit = 0; // 0 - analyze all documents
var structureType = structureTypes.type;
// =====================================

var getValueType = (value) => {
  if (value === null) {
    return 'null';
  }

  var valueType = typeof value;

  if (valueType !== 'object') {
    return valueType;
  }

  if (value instanceof Date) {
    return 'date';
  }
};

var buildTypeStructureForList = (documentsList, initStructure = {}) => {
  var structure = Object.assign({}, initStructure);

  documentsList.forEach((doc) => {
    Object.keys(doc).forEach((key) => {
      var types = structure[key];
      var value = doc[key];

      if (Array.isArray(value)) {
        structure[key] = buildTypeStructureForList(value, types || {});
      } else {
        var valueType = getValueType(value);

        if (types) {
          if (!types.includes(valueType)) {
            structure[key] = `${structure[key]}, ${valueType}`;
          }
        } else {
          structure[key] = valueType;
        }
      }
    });
  });

  return structure;
};

var buildTypeCountStructureForList = (documentsList, initStructure = {}) => {
  var structure = Object.assign({}, initStructure);

  documentsList.forEach((doc) => {
    Object.keys(doc).forEach((key) => {
      var types = structure[key];
      var value = doc[key];

      if (Array.isArray(value)) {
        structure[key] = buildTypeCountStructureForList(value, types || {});
      } else {
        var valueType = typeof value;

        if (types) {
          var typeCount = types[valueType] || 0;

          structure[key][valueType] = typeCount + 1;
        } else {
          structure[key] = { [valueType]: 1 };
        }
      }
    });
  });

  return structure;
};

var addCountRecord = (allDataCursor, structure) => {
  return Object.assign({}, { '@allDocumentsCount@': allDataCursor.count() }, structure);
};

var getCollectionStructure = (collectionName, limit = 0, structureType = structureTypes.type) => {
  var cursor = db.getCollection(collectionName).find({});
  var limitedCursor = limit > 0 ? cursor.limit(limit) : cursor;

  if (structureType === structureTypes.type) {
    return addCountRecord(
      cursor,
      buildTypeStructureForList(limitedCursor)
    );
  } else if (structureType === structureTypes.typeCount) {
    return addCountRecord(
      cursor,
      buildTypeCountStructureForList(limitedCursor)
    );
  }

  return {
    error: 'Structure type is invalid',
  };
};

getCollectionStructure(collectionName, limit, structureType);