Struct JsString 

pub struct JsString { /* private fields */ }

A Latin1 or UTF-16–encoded, reference counted, immutable string.

This is pretty similar to a Rc<[u16]>, but without the length metadata associated with the Rc fat pointer. Instead, the length of every string is stored on the heap, along with its reference counter and its data.

The string can be latin1 (stored as a byte for space efficiency) or U16 encoding.

We define some commonly used string constants in an interner. For these strings, we don’t allocate memory on the heap to reduce the overhead of memory allocation and reference counting.

Implementations

impl JsString

pub const fn from_static_js_string(src: &'static StaticJsString) -> Self

Create a JsString from a static js string.

pub fn iter(&self) -> Iter<'_>

Create an iterator over the JsString.

pub fn windows(&self, size: usize) -> Windows<'_>

Create an iterator over overlapping subslices of length size.

pub fn as_str(&self) -> JsStr<'_>

Obtains the underlying &[u16] slice of a JsString

pub fn concat(x: JsStr<'_>, y: JsStr<'_>) -> Self

Creates a new JsString from the concatenation of x and y.

pub fn concat_array(strings: &[JsStr<'_>]) -> Self

Creates a new JsString from the concatenation of every element of strings.

pub fn to_std_string_escaped(&self) -> String

Decodes a JsString into a String, replacing invalid data with its escaped representation in 4 digit hexadecimal.

pub fn to_std_string_lossy(&self) -> String

Decodes a JsString into a String, replacing invalid data with the replacement character U+FFFD.

pub fn to_std_string(&self) -> Result<String, FromUtf16Error>

Decodes a JsString into a String, returning

Errors

FromUtf16Error if it contains any invalid data.

pub fn to_std_string_with_surrogates( &self, ) -> impl Iterator<Item = Result<String, u16>> + '_

Decodes a JsString into an iterator of Result<String, u16>, returning surrogates as errors.

pub fn map_valid_segments<F>(&self, f: F) -> Self

where F: FnMut(String) -> String,

Maps the valid segments of an UTF16 string and leaves the unpaired surrogates unchanged.

pub fn code_points(&self) -> impl Iterator<Item = CodePoint> + Clone + '_

Gets an iterator of all the Unicode codepoints of a JsString.

pub fn index_of( &self, search_value: JsStr<'_>, from_index: usize, ) -> Option<usize>

Abstract operation StringIndexOf ( string, searchValue, fromIndex )

Note: Instead of returning an isize with -1 as the “not found” value, we make use of the type system and return Option<usize> with None as the “not found” value.

More information:

• ECMAScript reference

pub fn code_point_at(&self, position: usize) -> CodePoint

Abstract operation CodePointAt( string, position ).

The abstract operation CodePointAt takes arguments string (a String) and position (a non-negative integer) and returns a Record with fields [[CodePoint]] (a code point), [[CodeUnitCount]] (a positive integer), and [[IsUnpairedSurrogate]] (a Boolean). It interprets string as a sequence of UTF-16 encoded code points, as described in 6.1.4, and reads from it a single code point starting with the code unit at index position.

More information:

• ECMAScript reference

Panics

If position is smaller than size of string.

pub fn to_number(&self) -> f64

Abstract operation StringToNumber ( str )

More information:

• ECMAScript reference

pub fn len(&self) -> usize

Get the length of the JsString.

pub fn is_empty(&self) -> bool

Return true if the JsString is emtpy.

pub fn to_vec(&self) -> Vec<u16>

Convert the JsString into a Vec<U16>.

pub fn contains(&self, element: u8) -> bool

Check if the JsString contains a byte.

pub fn trim(&self) -> JsStr<'_>

Trim whitespace from the start and end of the JsString.

pub fn trim_start(&self) -> JsStr<'_>

Trim whitespace from the start of the JsString.

pub fn trim_end(&self) -> JsStr<'_>

Trim whitespace from the end of the JsString.

pub fn is_static(&self) -> bool

Check if the JsString is static.

pub fn get<'a, I>(&'a self, index: I) -> Option<I::Value>

where I: JsSliceIndex<'a>,

Get the element a the given index, None otherwise.

pub unsafe fn get_unchecked<'a, I>(&'a self, index: I) -> I::Value

where I: JsSliceIndex<'a>,

Returns an element or subslice depending on the type of index, without doing bounds check.

Safety

Caller must ensure the index is not out of bounds

pub fn get_expect<'a, I>(&'a self, index: I) -> I::Value

where I: JsSliceIndex<'a>,

Get the element a the given index.

Panics

If the index is out of bounds.

pub fn refcount(&self) -> Option<usize>

Gets the number of JsStrings which point to this allocation.

pub fn display_escaped(&self) -> JsStrDisplayEscaped<'_>

Gets a displayable escaped string. This may be faster and has fewer allocations than format!("{}", str.to_string_escaped()) when displaying.

pub fn display_lossy(&self) -> JsStrDisplayLossy<'_>

Gets a displayable lossy string. This may be faster and has fewer allocations than format!("{}", str.to_string_lossy()) when displaying.

Trait Implementations

impl Clone for JsString

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for JsString

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

Formats the value using the given formatter.

impl Default for JsString

fn default() -> Self

Returns the “default value” for a type.

impl Drop for JsString

fn drop(&mut self)

Executes the destructor for this type.

impl From<&[JsString]> for JsString

fn from(value: &[JsString]) -> Self

Converts to this type from the input type.

impl From<&[u16]> for JsString

fn from(s: &[u16]) -> Self

Converts to this type from the input type.

impl<const N: usize> From<&[u16; N]> for JsString

fn from(s: &[u16; N]) -> Self

Converts to this type from the input type.

impl<'a> From<&'a JsString> for JsStr<'a>

fn from(value: &'a JsString) -> Self

Converts to this type from the input type.

impl From<&str> for JsString

fn from(s: &str) -> Self

Converts to this type from the input type.

impl From<JsStr<'_>> for JsString

fn from(value: JsStr<'_>) -> Self

Converts to this type from the input type.

impl From<String> for JsString

fn from(s: String) -> Self

Converts to this type from the input type.

impl FromStr for JsString

type Err = Infallible

The associated error which can be returned from parsing.

fn from_str(s: &str) -> Result<Self, Self::Err>

Parses a string s to return a value of this type.

impl Hash for JsString

fn hash<H: Hasher>(&self, state: &mut H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<'a> IntoIterator for &'a JsString

type IntoIter = Iter<'a>

Which kind of iterator are we turning this into?

type Item = u16

The type of the elements being iterated over.

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl Ord for JsString

fn cmp(&self, other: &Self) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq<&str> for JsString

fn eq(&self, other: &&str) -> 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 PartialEq<[u16]> for JsString

fn eq(&self, other: &[u16]) -> 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<const N: usize> PartialEq<[u16; N]> for JsString

fn eq(&self, other: &[u16; N]) -> 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 PartialEq<JsStr<'_>> for JsString

fn eq(&self, other: &JsStr<'_>) -> 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 PartialEq<JsString> for [u16]

fn eq(&self, other: &JsString) -> 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<const N: usize> PartialEq<JsString> for [u16; N]

fn eq(&self, other: &JsString) -> 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 PartialEq<JsString> for JsStr<'_>

fn eq(&self, other: &JsString) -> 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 PartialEq<JsString> for str

fn eq(&self, other: &JsString) -> 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 PartialEq<str> for JsString

fn eq(&self, other: &str) -> 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 PartialEq for JsString

fn eq(&self, other: &Self) -> 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 PartialOrd for JsString

fn partial_cmp(&self, other: &Self) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Eq for JsString