Aggregation pipeline $set a value to boolean whether $and is true or false

Question

In my aggregation pipeline, I am trying to set a value to true if several conditions are matched. I will be adding more $and conditions later, but it doesn't even work with one condition.

These are the things I have tried:

    {
      $set: {
        someValue: {
          $and: [
            {
              'ratePlans.maxAdvBookDays': {
                $gte: advBookDays,
              },
            },
          ],
        }
      }
    }

    {
      $set: {
        someValue: {
          $and: [
            {
              $toBool: {
                'ratePlans.maxAdvBookDays': {
                  $gte: advBookDays,
                },
              },
            }
          ],
        }
      }
    }

    {
      $set: {
        someValue: {
          $cond: {
            if: {
              $and: [
                {
                  'ratePlans.maxAdvBookDays': {
                    $gte: advBookDays,
                  },
                },
              ],
            },
            then: 'then',
            else: 'else',
          }
        }
      }
    }

In each case, I get the following error:

MongoServerError: Invalid $set :: caused by :: FieldPath field names may not contain '.'.

However, when hard-coding the boolean values in, it does seem to work:

    {
      $set: {
        someValue: {
          $and: [
            true, true, false, true
          ],
        }
      }
    },

Answer 1

db.collection.aggregate([
  {
    $set: {
      someValue: {
        $cond: {
          if: {
            $and: [
              {
                $gte: [ "$ratePlans.maxAdvBookDays", 2 ]
              }
            ]
          },
          then: "then",
          else: "else"
        }
      }
    }
  }
])

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