Add note to lacking worklet support

.config/topic.dic

@@ -1,4 +1,4 @@
-17
+18
 1G
 1M
 1ns
@@ -16,3 +16,4 @@ v1
 Versioning
 WASI
 Wasm
+worklet

README.md

@@ -40,13 +40,21 @@ which case multiple ecosystems could be supported.
 
 ## Note
 
+### Ticking during sleep
+
 Currently a known bug is affecting browsers on operating system other then
 Windows. This bug prevents [`Instant`] from continuing to tick when the
 context is asleep. This doesn't necessarily conflict with Rusts requirements
 of [`Instant`], but might still be unexpected.
 
 See [the MDN documentation on this](https://developer.mozilla.org/en-US/docs/Web/API/Performance/now#ticking_during_sleep) for more information.
 
+### Context support
+
+The implementation of [`Instant::now()`] relies on the availability of the
+[`Performance` object], a lack thereof will cause a panic. This can happen
+if called from a [worklet].
+
 ## Usage
 
 You can simply import the types you need:
@@ -105,6 +113,7 @@ conditions.
 [CONTRIBUTING]: https://github.com/daxpedda/web-time/blob/v1.0.0/CONTRIBUTING.md
 [LICENSE-MIT]: https://github.com/daxpedda/web-time/blob/v1.0.0/LICENSE-MIT
 [LICENSE-APACHE]: https://github.com/daxpedda/web-time/blob/v1.0.0/LICENSE-APACHE
+[worklet]: https://developer.mozilla.org/en-US/docs/Web/API/Worklet
 [`Date.now()`]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/now
 [`Instant`]: https://doc.rust-lang.org/std/time/struct.Instant.html
 [`Instant::now()`]: https://doc.rust-lang.org/std/time/struct.Instant.html#method.now
@@ -113,4 +122,5 @@ conditions.
 [`std::time`]: https://doc.rust-lang.org/stable/std/time/
 [`performance.now()`]: https://developer.mozilla.org/en-US/docs/Web/API/Performance/now
 [`Performance.timeOrigin`]: https://developer.mozilla.org/en-US/docs/Web/API/Performance/timeOrigin
+[`Performance` object]: https://developer.mozilla.org/en-US/docs/Web/API/performance_property
 [`wasm-bindgen`]: https://crates.io/crates/wasm-bindgen

src/lib.rs

@@ -32,13 +32,21 @@
 //!
 //! # Note
 //!
+//! ## Ticking during sleep
+//!
 //! Currently a known bug is affecting browsers on operating system other then
 //! Windows. This bug prevents [`Instant`] from continuing to tick when the
 //! context is asleep. This doesn't necessarily conflict with Rusts requirements
 //! of [`Instant`], but might still be unexpected.
 //!
 //! See [the MDN documentation on this](https://developer.mozilla.org/en-US/docs/Web/API/Performance/now#ticking_during_sleep) for more information.
 //!
+//! ## Context support
+//!
+//! The implementation of [`Instant::now()`] relies on the availability of the
+//! [`Performance` object], a lack thereof will cause a panic. This can happen
+//! if called from a [worklet].
+//!
 //! # Usage
 //!
 //! You can simply import the types you need:
@@ -97,6 +105,7 @@
 //! [CONTRIBUTING]: https://github.com/daxpedda/web-time/blob/v1.0.0/CONTRIBUTING.md
 //! [LICENSE-MIT]: https://github.com/daxpedda/web-time/blob/v1.0.0/LICENSE-MIT
 //! [LICENSE-APACHE]: https://github.com/daxpedda/web-time/blob/v1.0.0/LICENSE-APACHE
+//! [worklet]: https://developer.mozilla.org/en-US/docs/Web/API/Worklet
 //! [`Date.now()`]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/now
 //! [`Instant`]: https://doc.rust-lang.org/std/time/struct.Instant.html
 //! [`Instant::now()`]: https://doc.rust-lang.org/std/time/struct.Instant.html#method.now
@@ -105,6 +114,7 @@
 //! [`std::time`]: https://doc.rust-lang.org/stable/std/time/
 //! [`performance.now()`]: https://developer.mozilla.org/en-US/docs/Web/API/Performance/now
 //! [`Performance.timeOrigin`]: https://developer.mozilla.org/en-US/docs/Web/API/Performance/timeOrigin
+//! [`Performance` object]: https://developer.mozilla.org/en-US/docs/Web/API/performance_property
 //! [`wasm-bindgen`]: https://crates.io/crates/wasm-bindgen
 
 #![cfg_attr(docsrs, feature(doc_cfg))]

src/time/instant.rs

@@ -16,6 +16,14 @@ pub struct Instant(Duration);
 
 impl Instant {
 	/// See [`std::time::Instant::now()`].
+	///
+	/// # Panics
+	///
+	/// This call will panic if the [`Performance` object] was not found, e.g.
+	/// calling from a [worklet].
+	///
+	/// [`Performance` object]: https://developer.mozilla.org/en-US/docs/Web/API/performance_property
+	/// [worklet]: https://developer.mozilla.org/en-US/docs/Web/API/Worklet
 	#[must_use]
 	pub fn now() -> Self {
 		let now = PERFORMANCE.with(|performance| {