Struct ValueView 

pub struct ValueView<'s>(/* private fields */);

Returns a view onto a string’s contents.

WARNING: This does not copy the string’s contents, and will therefore be invalidated if the GC can move the string while the ValueView is alive. It is therefore required that no GC or allocation can happen while there is an active ValueView. This requirement may be relaxed in the future.

V8 strings are either encoded as one-byte or two-bytes per character.

Implementations

impl<'s> ValueView<'s>

pub fn new(isolate: &mut Isolate, string: Local<'s, String>) -> Self

pub fn data(&self) -> ValueViewData<'_>

pub fn as_str(&self) -> Option<&str>

Returns a zero-copy &str if the string is one-byte and pure ASCII.

This is the fastest way to access a V8 string’s contents as a Rust &str — no allocation, no copy, no transcoding. Returns None for strings that contain non-ASCII Latin-1 bytes or are two-byte encoded.

The returned reference is valid as long as this ValueView is alive.

pub fn to_cow_lossy(&self) -> Cow<'_, str>

Returns the string contents as a Cow<str>.

• One-byte ASCII: returns Cow::Borrowed(&str) — true zero-copy.
• One-byte Latin-1 (non-ASCII): transcodes to UTF-8, returns Cow::Owned.
• Two-byte (UTF-16): transcodes to UTF-8 via std::string::String::from_utf16_lossy, returns Cow::Owned.

For the common case of ASCII strings this is zero-copy. The Latin-1 transcoding uses a SIMD-friendly loop that processes 8 bytes at a time.

Trait Implementations

impl Drop for ValueView<'_>

fn drop(&mut self)

Executes the destructor for this type.