Tish - Native Performance, Familiar Syntax

Overview

Date represents a single moment in time as the number of milliseconds since the Unix epoch (1970-01-01T00:00:00Z). The constructor and all instance methods work identically across every Tish backend — the interpreter, the bytecode VM, and native (AOT) compiled binaries.

Tish runs Date in UTC. getTimezoneOffset() is always 0, and the local-time getters (getFullYear, getHours, …) are exact aliases of their getUTC* counterparts. The core runtime ships no timezone database, which keeps it small and WebAssembly-friendly. getTime, valueOf, the getUTC* family, and toISOString() are therefore fully deterministic on every machine.

Constructor

Form	Result
`new Date()`	The current moment (`Date.now()`).
`new Date(ms)`	From epoch milliseconds.
`new Date(isoString)`	Parses ISO-8601 (`YYYY-MM-DD` or `YYYY-MM-DDTHH:MM:SS.sss` with optional `Z`/`±HH:MM`).
`new Date(year, month, day?, h?, m?, s?, ms?)`	From UTC components — `month` is 0-based (January = 0). Omitted fields default to `0` (or `1` for `day`).

Static methods

Method	Description
`Date.now()`	Current time in epoch milliseconds.
`Date.parse(string)`	Epoch milliseconds for an ISO-8601 string, or `NaN` if unparseable.
`Date.UTC(year, month, day?, h?, m?, s?, ms?)`	Epoch milliseconds for the given UTC components (`month` 0-based).

Instance methods

Method	Description
`getTime()` / `valueOf()`	Epoch milliseconds.
`setTime(ms)`	Set the instant; returns `ms`.
`toISOString()` / `toJSON()`	ISO-8601 string (`…Z`).
`toString()` / `toUTCString()` / `toDateString()` / `toTimeString()`	Human-readable UTC renderings.
`getUTCFullYear()` … `getUTCMilliseconds()`	UTC calendar fields. `getUTCMonth()` is 0-based; `getUTCDay()` is 0 (Sun) … 6 (Sat).
`getFullYear()` … `getMilliseconds()`	Local-time fields — identical to the `getUTC*` family (Tish is UTC).
`getTimezoneOffset()`	Always `0`.

Examples

let d = new Date(1623242096789)
d.toISOString()        // "2021-06-09T12:34:56.789Z"
d.getUTCFullYear()     // 2021
d.getUTCMonth()        // 5  (June — 0-based)
d.getUTCDate()         // 9
d.getUTCDay()          // 3  (Wednesday)
 
Date.UTC(2021, 5, 9, 12, 34, 56, 789)   // 1623242096789
Date.parse("2021-06-09T12:34:56.789Z")  // 1623242096789
 
let t = new Date(0)
t.setTime(1000)
t.toISOString()        // "1970-01-01T00:00:01.000Z"
 
// Leap day round-trips correctly.
new Date(Date.UTC(2020, 1, 29)).toISOString()  // "2020-02-29T00:00:00.000Z"

Compatibility notes

UTC only. Local-time methods return UTC values and getTimezoneOffset() is 0 (see the note above). Code that needs the host timezone should run on the --target js backend.
new Date(year, month, …) is interpreted as UTC, whereas standard JavaScript interprets the multi-argument form in local time. With Tish's UTC model the two coincide.
Setters other than setTime (e.g. setUTCHours) are not yet implemented; build a new Date from Date.UTC(...) instead.