$dateFromString

  • 04/11/2025

The $dateFromString operator is used to convert a date/time string to a date object in MongoDB. This operation can be useful when dealing with string representations of dates that need to be manipulated or queried as date objects.

Syntax

{ $dateFromString: { dateString: <string>, format: <string>, timezone: <string>, onError: <expression>, onNull: <expression> } }

Parameters

Parameter Description
dateString The date/time string to convert to a date object.
format (Optional) The date format specification of the dateString.
timezone (Optional) The timezone to use to format the date.
onError (Optional) The value to return if an error occurs while parsing the dateString.
onNull (Optional) The value to return if the dateString is null or missing.

Example

Converting promotional event dates

This example demonstrates how to convert the startDate and endDate of promotional events from string representations to date objects.

db.collection.aggregate([
  {
    $project: {
      eventName: 1,
      startDate: {
        $dateFromString: {
          dateString: {
            $concat: [
              { $toString: "$promotionEvents.promotionalDates.startDate.Year" },
              "-",
              { $toString: "$promotionEvents.promotionalDates.startDate.Month" },
              "-",
              { $toString: "$promotionEvents.promotionalDates.startDate.Day" }
            ]
          }
        }
      },
      endDate: {
        $dateFromString: {
          dateString: {
            $concat: [
              { $toString: "$promotionEvents.promotionalDates.endDate.Year" },
              "-",
              { $toString: "$promotionEvents.promotionalDates.endDate.Month" },
              "-",
              { $toString: "$promotionEvents.promotionalDates.endDate.Day" }
            ]
          }
        }
      }
    }
  }
])

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