Struct js_sys::JsString

#[repr(transparent)]pub struct JsString { /* fields omitted */ }

Implementations

impl JsString

pub fn length(&self) -> u32

The length property of a String object indicates the length of a string, in UTF-16 code units.

MDN documentation

impl JsString

pub fn char_at(&self, index: u32) -> JsString

The String object’s charAt() method returns a new string consisting of the single UTF-16 code unit located at the specified offset into the string.

MDN documentation

impl JsString

pub fn char_code_at(&self, index: u32) -> f64

The charCodeAt() method returns an integer between 0 and 65535 representing the UTF-16 code unit at the given index (the UTF-16 code unit matches the Unicode code point for code points representable in a single UTF-16 code unit, but might also be the first code unit of a surrogate pair for code points not representable in a single UTF-16 code unit, e.g. Unicode code points > 0x10000). If you want the entire code point value, use codePointAt().

Returns NaN if index is out of range.

MDN documentation

impl JsString

pub fn code_point_at(&self, pos: u32) -> JsValue

The codePointAt() method returns a non-negative integer that is the Unicode code point value.

MDN documentation

impl JsString

pub fn concat(&self, string_2: &JsValue) -> JsString

The concat() method concatenates the string arguments to the calling string and returns a new string.

MDN documentation

impl JsString

pub fn ends_with(&self, search_string: &str, length: i32) -> bool

The endsWith() method determines whether a string ends with the characters of a specified string, returning true or false as appropriate.

MDN documentation

impl JsString

pub fn from_char_code(char_codes: &[u16]) -> JsString

The static String.fromCharCode() method returns a string created from the specified sequence of UTF-16 code units.

MDN documentation

Notes

There are a few bindings to from_char_code in js-sys: from_char_code1, from_char_code2, etc… with different arities.

Additionally, this function accepts u16 for character codes, but fixing others requires a breaking change release (see https://github.com/rustwasm/wasm-bindgen/issues/1460 for details).

impl JsString

pub fn from_char_code1(a: u32) -> JsString

MDN documentation

impl JsString

pub fn from_char_code2(a: u32, b: u32) -> JsString

MDN documentation

impl JsString

pub fn from_char_code3(a: u32, b: u32, c: u32) -> JsString

MDN documentation

impl JsString

pub fn from_char_code4(a: u32, b: u32, c: u32, d: u32) -> JsString

MDN documentation

impl JsString

pub fn from_char_code5(a: u32, b: u32, c: u32, d: u32, e: u32) -> JsString

MDN documentation

impl JsString

pub fn from_code_point(code_points: &[u32]) -> Result<JsString, JsValue>

The static String.fromCodePoint() method returns a string created by using the specified sequence of code points.

MDN documentation

Exceptions

A RangeError is thrown if an invalid Unicode code point is given

Notes

There are a few bindings to from_code_point in js-sys: from_code_point1, from_code_point2, etc… with different arities.

impl JsString

pub fn from_code_point1(a: u32) -> Result<JsString, JsValue>

MDN documentation

impl JsString

pub fn from_code_point2(a: u32, b: u32) -> Result<JsString, JsValue>

MDN documentation

impl JsString

pub fn from_code_point3(a: u32, b: u32, c: u32) -> Result<JsString, JsValue>

MDN documentation

impl JsString

pub fn from_code_point4(
    a: u32,
    b: u32,
    c: u32,
    d: u32
) -> Result<JsString, JsValue>

MDN documentation

impl JsString

pub fn from_code_point5(
    a: u32,
    b: u32,
    c: u32,
    d: u32,
    e: u32
) -> Result<JsString, JsValue>

MDN documentation

impl JsString

pub fn includes(&self, search_string: &str, position: i32) -> bool

The includes() method determines whether one string may be found within another string, returning true or false as appropriate.

MDN documentation

impl JsString

pub fn index_of(&self, search_value: &str, from_index: i32) -> i32

The indexOf() method returns the index within the calling String object of the first occurrence of the specified value, starting the search at fromIndex. Returns -1 if the value is not found.

MDN documentation

impl JsString

pub fn last_index_of(&self, search_value: &str, from_index: i32) -> i32

The lastIndexOf() method returns the index within the calling String object of the last occurrence of the specified value, searching backwards from fromIndex. Returns -1 if the value is not found.

MDN documentation

impl JsString

pub fn locale_compare(
    &self,
    compare_string: &str,
    locales: &Array,
    options: &Object
) -> i32

The localeCompare() method returns a number indicating whether a reference string comes before or after or is the same as the given string in sort order.

MDN documentation

impl JsString

pub fn match_(&self, pattern: &RegExp) -> Option<Object>

The match() method retrieves the matches when matching a string against a regular expression.

MDN documentation

impl JsString

pub fn normalize(&self, form: &str) -> JsString

The normalize() method returns the Unicode Normalization Form of a given string (if the value isn’t a string, it will be converted to one first).

MDN documentation

impl JsString

pub fn pad_end(&self, target_length: u32, pad_string: &str) -> JsString

The padEnd() method pads the current string with a given string (repeated, if needed) so that the resulting string reaches a given length. The padding is applied from the end (right) of the current string.

MDN documentation

impl JsString

pub fn pad_start(&self, target_length: u32, pad_string: &str) -> JsString

The padStart() method pads the current string with another string (repeated, if needed) so that the resulting string reaches the given length. The padding is applied from the start (left) of the current string.

MDN documentation

impl JsString

pub fn repeat(&self, count: i32) -> JsString

The repeat() method constructs and returns a new string which contains the specified number of copies of the string on which it was called, concatenated together.

MDN documentation

impl JsString

pub fn replace(&self, pattern: &str, replacement: &str) -> JsString

The replace() method returns a new string with some or all matches of a pattern replaced by a replacement. The pattern can be a string or a RegExp, and the replacement can be a string or a function to be called for each match.

Note: The original string will remain unchanged.

MDN documentation

impl JsString

pub fn replace_with_function(
    &self,
    pattern: &str,
    replacement: &Function
) -> JsString

MDN documentation

impl JsString

pub fn replace_by_pattern(
    &self,
    pattern: &RegExp,
    replacement: &str
) -> JsString

impl JsString

pub fn replace_by_pattern_with_function(
    &self,
    pattern: &RegExp,
    replacement: &Function
) -> JsString

MDN documentation

impl JsString

pub fn search(&self, pattern: &RegExp) -> i32

The search() method executes a search for a match between a regular expression and this String object.

MDN documentation

impl JsString

pub fn slice(&self, start: u32, end: u32) -> JsString

The slice() method extracts a section of a string and returns it as a new string, without modifying the original string.

MDN documentation

impl JsString

pub fn split(&self, separator: &str) -> Array

The split() method splits a String object into an array of strings by separating the string into substrings, using a specified separator string to determine where to make each split.

MDN documentation

impl JsString

pub fn split_limit(&self, separator: &str, limit: u32) -> Array

MDN documentation

impl JsString

pub fn split_by_pattern(&self, pattern: &RegExp) -> Array

MDN documentation

impl JsString

pub fn split_by_pattern_limit(&self, pattern: &RegExp, limit: u32) -> Array

MDN documentation

impl JsString

pub fn starts_with(&self, search_string: &str, position: u32) -> bool

The startsWith() method determines whether a string begins with the characters of a specified string, returning true or false as appropriate.

MDN documentation

impl JsString

pub fn substring(&self, index_start: u32, index_end: u32) -> JsString

The substring() method returns the part of the string between the start and end indexes, or to the end of the string.

MDN documentation

impl JsString

pub fn substr(&self, start: i32, length: i32) -> JsString

The substr() method returns the part of a string between the start index and a number of characters after it.

MDN documentation

impl JsString

pub fn to_locale_lower_case(&self, locale: Option<&str>) -> JsString

The toLocaleLowerCase() method returns the calling string value converted to lower case, according to any locale-specific case mappings.

MDN documentation

impl JsString

pub fn to_locale_upper_case(&self, locale: Option<&str>) -> JsString

The toLocaleUpperCase() method returns the calling string value converted to upper case, according to any locale-specific case mappings.

MDN documentation

impl JsString

pub fn to_lower_case(&self) -> JsString

The toLowerCase() method returns the calling string value converted to lower case.

MDN documentation

impl JsString

pub fn to_string(&self) -> JsString

The toString() method returns a string representing the specified object.

MDN documentation

impl JsString

pub fn to_upper_case(&self) -> JsString

The toUpperCase() method returns the calling string value converted to uppercase (the value will be converted to a string if it isn’t one).

MDN documentation

impl JsString

pub fn trim(&self) -> JsString

The trim() method removes whitespace from both ends of a string. Whitespace in this context is all the whitespace characters (space, tab, no-break space, etc.) and all the line terminator characters (LF, CR, etc.).

MDN documentation

impl JsString

pub fn trim_end(&self) -> JsString

The trimEnd() method removes whitespace from the end of a string. trimRight() is an alias of this method.

MDN documentation

impl JsString

pub fn trim_right(&self) -> JsString

The trimEnd() method removes whitespace from the end of a string. trimRight() is an alias of this method.

MDN documentation

impl JsString

pub fn trim_start(&self) -> JsString

The trimStart() method removes whitespace from the beginning of a string. trimLeft() is an alias of this method.

MDN documentation

impl JsString

pub fn trim_left(&self) -> JsString

The trimStart() method removes whitespace from the beginning of a string. trimLeft() is an alias of this method.

MDN documentation

impl JsString

pub fn value_of(&self) -> JsString

The valueOf() method returns the primitive value of a String object.

MDN documentation

impl JsString

pub fn raw(
    call_site: &Object,
    substitutions: &Array
) -> Result<JsString, JsValue>

The static raw() method is a tag function of template literals, similar to the r prefix in Python or the @ prefix in C# for string literals.

MDN documentation

impl JsString

pub fn raw_0(call_site: &Object) -> Result<JsString, JsValue>

The static raw() method is a tag function of template literals, similar to the r prefix in Python or the @ prefix in C# for string literals.

MDN documentation

impl JsString

pub fn raw_1(
    call_site: &Object,
    substitutions_1: &str
) -> Result<JsString, JsValue>

The static raw() method is a tag function of template literals, similar to the r prefix in Python or the @ prefix in C# for string literals.

MDN documentation

impl JsString

pub fn raw_2(
    call_site: &Object,
    substitutions_1: &str,
    substitutions_2: &str
) -> Result<JsString, JsValue>

The static raw() method is a tag function of template literals, similar to the r prefix in Python or the @ prefix in C# for string literals.

MDN documentation

impl JsString

pub fn raw_3(
    call_site: &Object,
    substitutions_1: &str,
    substitutions_2: &str,
    substitutions_3: &str
) -> Result<JsString, JsValue>

The static raw() method is a tag function of template literals, similar to the r prefix in Python or the @ prefix in C# for string literals.

MDN documentation

impl JsString

pub fn raw_4(
    call_site: &Object,
    substitutions_1: &str,
    substitutions_2: &str,
    substitutions_3: &str,
    substitutions_4: &str
) -> Result<JsString, JsValue>

The static raw() method is a tag function of template literals, similar to the r prefix in Python or the @ prefix in C# for string literals.

MDN documentation

impl JsString

pub fn raw_5(
    call_site: &Object,
    substitutions_1: &str,
    substitutions_2: &str,
    substitutions_3: &str,
    substitutions_4: &str,
    substitutions_5: &str
) -> Result<JsString, JsValue>

The static raw() method is a tag function of template literals, similar to the r prefix in Python or the @ prefix in C# for string literals.

MDN documentation

impl JsString

pub fn raw_6(
    call_site: &Object,
    substitutions_1: &str,
    substitutions_2: &str,
    substitutions_3: &str,
    substitutions_4: &str,
    substitutions_5: &str,
    substitutions_6: &str
) -> Result<JsString, JsValue>

The static raw() method is a tag function of template literals, similar to the r prefix in Python or the @ prefix in C# for string literals.

MDN documentation

impl JsString

pub fn raw_7(
    call_site: &Object,
    substitutions_1: &str,
    substitutions_2: &str,
    substitutions_3: &str,
    substitutions_4: &str,
    substitutions_5: &str,
    substitutions_6: &str,
    substitutions_7: &str
) -> Result<JsString, JsValue>

The static raw() method is a tag function of template literals, similar to the r prefix in Python or the @ prefix in C# for string literals.

MDN documentation

impl JsString

pub fn try_from(val: &JsValue) -> Option<&JsString>

👎 Deprecated:

recommended to use dyn_ref instead which is now equivalent

Returns the JsString value of this JS value if it’s an instance of a string.

If this JS value is not an instance of a string then this returns None.

pub fn is_valid_utf16(&self) -> bool

Returns whether this string is a valid UTF-16 string.

This is useful for learning whether String::from(..) will return a lossless representation of the JS string. If this string contains unpaired surrogates then String::from will succeed but it will be a lossy representation of the JS string because unpaired surrogates will become replacement characters.

If this function returns false then to get a lossless representation of the string you’ll need to manually use the iter method (or the char_code_at accessor) to view the raw character codes.

For more information, see the documentation on JS strings vs Rust strings

pub fn iter<'a>(
    &'a self
) -> impl ExactSizeIterator<Item = u16> + DoubleEndedIterator<Item = u16> + 'a

Returns an iterator over the u16 character codes that make up this JS string.

This method will call char_code_at for each code in this JS string, returning an iterator of the codes in sequence.

pub fn as_char(&self) -> Option<char>

If this string consists of a single Unicode code point, then this method converts it into a Rust char without doing any allocations.

If this JS value is not a valid UTF-8 or consists of more than a single codepoint, then this returns None.

Note that a single Unicode code point might be represented as more than one code unit on the JavaScript side. For example, a JavaScript string "\uD801\uDC37" is actually a single Unicode code point U+10437 which corresponds to a character ‘𐐷’.

Methods from Deref<Target = Object>

pub fn constructor(&self) -> Function

The constructor property returns a reference to the Object constructor function that created the instance object.

MDN documentation

pub fn has_own_property(&self, property: &JsValue) -> bool

The hasOwnProperty() method returns a boolean indicating whether the object has the specified property as its own property (as opposed to inheriting it).

MDN documentation

pub fn is_prototype_of(&self, value: &JsValue) -> bool

The isPrototypeOf() method checks if an object exists in another object’s prototype chain.

MDN documentation

pub fn property_is_enumerable(&self, property: &JsValue) -> bool

The propertyIsEnumerable() method returns a Boolean indicating whether the specified property is enumerable.

MDN documentation

pub fn to_locale_string(&self) -> JsString

The toLocaleString() method returns a string representing the object. This method is meant to be overridden by derived objects for locale-specific purposes.

MDN documentation

pub fn to_string(&self) -> JsString

The toString() method returns a string representing the object.

MDN documentation

pub fn value_of(&self) -> Object

The valueOf() method returns the primitive value of the specified object.

MDN documentation

Methods from Deref<Target = JsValue>

pub const NULL: JsValue

pub const UNDEFINED: JsValue

pub const TRUE: JsValue

pub const FALSE: JsValue

pub fn as_f64(&self) -> Option<f64>

Returns the f64 value of this JS value if it’s an instance of a number.

If this JS value is not an instance of a number then this returns None.

pub fn is_string(&self) -> bool

Tests whether this JS value is a JS string.

pub fn as_string(&self) -> Option<String>

If this JS value is a string value, this function copies the JS string value into wasm linear memory, encoded as UTF-8, and returns it as a Rust String.

To avoid the copying and re-encoding, consider the JsString::try_from() function from js-sys instead.

If this JS value is not an instance of a string or if it’s not valid utf-8 then this returns None.

UTF-16 vs UTF-8

JavaScript strings in general are encoded as UTF-16, but Rust strings are encoded as UTF-8. This can cause the Rust string to look a bit different than the JS string sometimes. For more details see the documentation about the str type which contains a few caveats about the encodings.

pub fn as_bool(&self) -> Option<bool>

Returns the bool value of this JS value if it’s an instance of a boolean.

If this JS value is not an instance of a boolean then this returns None.

pub fn is_null(&self) -> bool

Tests whether this JS value is null

pub fn is_undefined(&self) -> bool

Tests whether this JS value is undefined

pub fn is_symbol(&self) -> bool

Tests whether the type of this JS value is symbol

pub fn is_object(&self) -> bool

Tests whether typeof self == "object" && self !== null.

pub fn is_function(&self) -> bool

Tests whether the type of this JS value is function.

pub fn is_truthy(&self) -> bool

Tests whether the value is “truthy”.

pub fn is_falsy(&self) -> bool

Tests whether the value is “falsy”.

Trait Implementations

impl AsRef<JsString> for JsString

fn as_ref(&self) -> &JsString

Performs the conversion.

impl AsRef<JsValue> for JsString

fn as_ref(&self) -> &JsValue

Performs the conversion.

impl AsRef<Object> for JsString

fn as_ref(&self) -> &Object

Performs the conversion.

impl Clone for JsString

fn clone(&self) -> JsString

Returns a copy of the value.

pub 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 Deref for JsString

type Target = Object

The resulting type after dereferencing.

fn deref(&self) -> &Object

Dereferences the value.

impl Eq for JsString

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

fn from(s: &'a str) -> Self

Performs the conversion.

impl From<JsString> for JsValue

fn from(obj: JsString) -> JsValue

Performs the conversion.

impl From<JsString> for Object

fn from(obj: JsString) -> Object

Performs the conversion.

impl From<JsValue> for JsString

fn from(obj: JsValue) -> JsString

Performs the conversion.

impl From<String> for JsString

fn from(s: String) -> Self

Performs the conversion.

impl From<char> for JsString

fn from(c: char) -> Self

Performs the conversion.

impl FromWasmAbi for JsString

type Abi = <JsValue as FromWasmAbi>::Abi

The wasm ABI type that this converts from when coming back out from the ABI boundary.

unsafe fn from_abi(js: Self::Abi) -> Self

Recover a Self from Self::Abi.

impl IntoWasmAbi for JsString

type Abi = <JsValue as IntoWasmAbi>::Abi

The wasm ABI type that this converts into when crossing the ABI boundary.

fn into_abi(self) -> Self::Abi

Convert self into Self::Abi so that it can be sent across the wasm ABI boundary.

impl<'a> IntoWasmAbi for &'a JsString

type Abi = <&'a JsValue as IntoWasmAbi>::Abi

The wasm ABI type that this converts into when crossing the ABI boundary.

fn into_abi(self) -> Self::Abi

Convert self into Self::Abi so that it can be sent across the wasm ABI boundary.

impl JsCast for JsString

fn instanceof(val: &JsValue) -> bool

Performs a dynamic instanceof check to see whether the JsValue provided is an instance of this type.

fn is_type_of(val: &JsValue) -> bool

Performs a dynamic check to see whether the JsValue provided is a value of this type.

fn unchecked_from_js(val: JsValue) -> Self

Performs a zero-cost unchecked conversion from a JsValue into an instance of Self

fn unchecked_from_js_ref(val: &JsValue) -> &Self

Performs a zero-cost unchecked conversion from a &JsValue into an instance of &Self.

pub fn has_type<T>(&self) -> bool where
    T: JsCast, 

Test whether this JS value has a type T.

pub fn dyn_into<T>(self) -> Result<T, Self> where
    T: JsCast, 

Performs a dynamic cast (checked at runtime) of this value into the target type T.

pub fn dyn_ref<T>(&self) -> Option<&T> where
    T: JsCast, 

Performs a dynamic cast (checked at runtime) of this value into the target type T.

pub fn unchecked_into<T>(self) -> T where
    T: JsCast, 

Performs a zero-cost unchecked cast into the specified type.

pub fn unchecked_ref<T>(&self) -> &T where
    T: JsCast, 

Performs a zero-cost unchecked cast into a reference to the specified type.

pub fn is_instance_of<T>(&self) -> bool where
    T: JsCast, 

Test whether this JS value is an instance of the type T.

impl OptionFromWasmAbi for JsString

fn is_none(abi: &Self::Abi) -> bool

Tests whether the argument is a “none” instance. If so it will be deserialized as None, and otherwise it will be passed to FromWasmAbi.

impl OptionIntoWasmAbi for JsString

fn none() -> Self::Abi

Returns an ABI instance indicating “none”, which JS will interpret as the None branch of this option.

impl<'a> OptionIntoWasmAbi for &'a JsString

fn none() -> Self::Abi

Returns an ABI instance indicating “none”, which JS will interpret as the None branch of this option.

impl<'a> PartialEq<&'a String> for JsString

fn eq(&self, other: &&'a String) -> bool

This method tests for self and other values to be equal, and is used by ==.

#[must_use]pub fn ne(&self, other: &Rhs) -> bool

This method tests for !=.

impl<'a> PartialEq<&'a str> for JsString

fn eq(&self, other: &&'a str) -> bool

This method tests for self and other values to be equal, and is used by ==.

#[must_use]pub fn ne(&self, other: &Rhs) -> bool

This method tests for !=.

impl PartialEq<JsString> for JsString

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

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=.

impl PartialEq<String> for JsString

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

This method tests for self and other values to be equal, and is used by ==.

#[must_use]pub fn ne(&self, other: &Rhs) -> bool

This method tests for !=.

impl PartialEq<str> for JsString

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

This method tests for self and other values to be equal, and is used by ==.

#[must_use]pub fn ne(&self, other: &Rhs) -> bool

This method tests for !=.

impl RefFromWasmAbi for JsString

type Abi = <JsValue as RefFromWasmAbi>::Abi

The wasm ABI type references to Self are recovered from.

type Anchor = ManuallyDrop<JsString>

The type that holds the reference to Self for the duration of the invocation of the function that has an &Self parameter. This is required to ensure that the lifetimes don’t persist beyond one function call, and so that they remain anonymous.

unsafe fn ref_from_abi(js: Self::Abi) -> Self::Anchor

Recover a Self::Anchor from Self::Abi.

impl StructuralEq for JsString

impl StructuralPartialEq for JsString

impl WasmDescribe for JsString

fn describe()