Enum Order 

pub enum Order {
    Smart,
    Year,
    Day,
    Month,
}

Variants

Smart

Default & recommended — Research-backed modern heuristic that delivers the highest real-world success rate while remaining predictable.

It uses the following prioritized rules (applied in this exact order):

1. Pure-numeric compact formats (≥ 6 digits with no separators, e.g. 240314153045, 20240315, YYMMDDHHMMSS): treated as Year-first (%Y%m%d / %y%m%d). These are overwhelmingly used in logs, filenames, databases, APIs, configs, and JSON for sortability.

2. Delimited formats that start with a plausible 4-digit year (1900–2100): treated as Year-first.

3. Numeric plausibility check (strongest universal signal):

   • First number is 13–31 → Day-first (international/European style).
   • First number is 1–12 and second number is 13–31 → Month-first (US style).

4. Strong ISO 8601 / timestamp markers (T connector, Z, numeric offsets, or IANA timezone names) → Year-first.

5. Fallback:

   • With the locale feature enabled: respects the system locale preference (Day-first in most of the world).
   • Without the locale feature: Day-first (global majority).

The / separator is deliberately ignored in the plausibility step because it is culturally ambiguous.

Once the preferred ordering is determined, the parser tries the corresponding ambiguous candidate formats (Year-first → Day-first → Month-first, or the reverse, depending on the detected order) and falls back gracefully.

Year

Force Year-first only (YYYY/MM/DD or YY/MM/DD)

Day

Force Day-first only (DD/MM/YYYY)

Month

Force Month-first only (MM/DD/YYYY)

Trait Implementations

impl Clone for Order

fn clone(&self) -> Order

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Order

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for Order

fn default() -> Order

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for Order

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for Order

fn eq(&self, other: &Order) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for Order

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Tsify for Order

const DECL: &'static str = "export type Order = \"Smart\" | \"Year\" | \"Day\" | \"Month\";"

const SERIALIZATION_CONFIG: SerializationConfig

type JsType = JsType

fn into_js(&self) -> Result<Self::JsType, Error>

where Self: Serialize,

fn from_js<T>(js: T) -> Result<Self, Error>

where T: Into<JsValue>, Self: DeserializeOwned,

impl Copy for Order

impl StructuralPartialEq for Order