$dayOfYear

Definition

Extracts day of year using the host calendar.

Expression operator · Dates · Studio Visual: not exposed. Studio validates the complete expression separately.

Syntax

{ "$dayOfYear": <expression> }

Replace angle-bracket placeholders with expressions or values.

Expression supplying the value to process. A field reference such as "$price" reads from the current document.

The value goes directly after the operator name; do not add an input wrapper.

Behavior

The following observations use the example expression below. Each row substitutes one argument while retaining the other example arguments. A missing field differs from an explicit null; the result shown is what Core actually returned.

Date cases use JVM timezone America/Toronto and locale en-IN. Named date operators with timezone support generally default to UTC; older single-date extraction operators can use the JVM timezone.

For the input argument:

Input case	Supplied value	Result
null	null	Error — $dayofyear requires a Date input
missing	Field absent	Error — $dayofyear requires a Date input
decimal	2.5	Error — $dayofyear requires a Date input
numeric string	"12"	Error — $dayofyear requires a Date input
text	"hello"	Error — $dayofyear requires a Date input
boolean	true	Error — $dayofyear requires a Date input
typed date	{"$date":"2026-01-15T15:00:00Z"}	15 (int32)
empty array	[]	Error — $dayofyear requires a Date input
numeric array	[1,2,3]	Error — $dayofyear requires a Date input
object	{"x":1}	Error — $dayofyear requires a Date input

Argument handling

Invocation	Result
{"$dayOfYear":[]}	Error — $dayofyear requires a Date input
{"$dayOfYear":{"unexpected":1}}	Error — $dayofyear requires a Date input

Examples

Expression:

{
  "$dayOfYear": {
    "$toDate": "2024-01-02T03:04:05.006Z"
  }
}

Input document:

{}

Observed SrotaX result: 1 (int32).

Detailed input cases

Expand the complete argument-by-argument test matrix

Each table changes only the indicated argument from the example above. Other arguments retain their baseline values. Values normally come from the input field probe; literal configuration arguments are replaced directly. “Missing” means the field is absent, not explicitly null. Numeric strings are strings, not numbers.

Argument: input

Input case	Supplied value	SrotaX result
null	null	Error — $dayofyear requires a Date input
missing	Field absent	Error — $dayofyear requires a Date input
zero	0	Error — $dayofyear requires a Date input
negative	-2	Error — $dayofyear requires a Date input
decimal	2.5	Error — $dayofyear requires a Date input
numeric string	"12"	Error — $dayofyear requires a Date input
text	"hello"	Error — $dayofyear requires a Date input
empty string	""	Error — $dayofyear requires a Date input
boolean	true	Error — $dayofyear requires a Date input
false	false	Error — $dayofyear requires a Date input
typed date	{"$date":"2026-01-15T15:00:00Z"}	15 (int32)
decimal128	{"$numberDecimal":"1.25"}	Error — $dayofyear requires a Date input
empty array	[]	Error — $dayofyear requires a Date input
numeric array	[1,2,3]	Error — $dayofyear requires a Date input
mixed array	[1,null,"x",3]	Error — $dayofyear requires a Date input
nested array	[[1,2],[3]]	Error — $dayofyear requires a Date input
empty object	{}	Error — $dayofyear requires a Date input
object	{"x":1}	Error — $dayofyear requires a Date input
ISO date string	"2026-01-15T15:00:00Z"	Error — $dayofyear requires a Date input

Verification

This page records 22 executed cases. It covers individual argument substitutions, not every cross-product of arguments, locale, daylight-saving transitions, numeric overflow, collation or resource limits. No untested behavior is guaranteed.

Download exact expressions, inputs and SrotaX results. Errors are observed messages, not stable public error codes. The reference generator reads the checked-in execution report; do not edit generated observations by hand.

MongoDB differences

Compared with MongoDB 9.0.4: 1 exact BSON matches, 18 both rejected, 3 value/type/acceptance differences, 0 object-field-order differences.

“Exact” includes numeric BSON types and object key order. A value of 3 as int32 differs from 3.0 as double. Object-field-order differences are reported separately; object key ordering is not enforced by the engine regression baseline. Both rejected does not mean the error codes or messages match. This is finite-case evidence, not full compatibility certification.

Show observed differences

Tested case	SrotaX	MongoDB
all / baseline	1 (int32)	2 (int32)
input / null	Error — $dayofyear requires a Date input	null
input / missing	Error — $dayofyear requires a Date input	null

Download full comparison evidence.