Struct js_sys::Map

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

Implementations

impl Map

pub fn clear(&self)

The clear() method removes all elements from a Map object.

MDN documentation

impl Map

pub fn delete(&self, key: &JsValue) -> bool

The delete() method removes the specified element from a Map object.

MDN documentation

impl Map

pub fn for_each(&self, callback: &mut dyn FnMut(JsValue, JsValue))

The forEach() method executes a provided function once per each key/value pair in the Map object, in insertion order. Note that in Javascript land the Key and Value are reversed compared to normal expectations:

Examples

let js_map = Map::new();
js_map.for_each(&mut |value, key| {
    // Do something here...
})

MDN documentation

impl Map

pub fn get(&self, key: &JsValue) -> JsValue

The get() method returns a specified element from a Map object.

MDN documentation

impl Map

pub fn has(&self, key: &JsValue) -> bool

The has() method returns a boolean indicating whether an element with the specified key exists or not.

MDN documentation

impl Map

pub fn new() -> Map

The Map object holds key-value pairs. Any value (both objects and primitive values) maybe used as either a key or a value.

MDN documentation

impl Map

pub fn set(&self, key: &JsValue, value: &JsValue) -> Map

The set() method adds or updates an element with a specified key and value to a Map object.

MDN documentation

impl Map

pub fn size(&self) -> u32

The value of size is an integer representing how many entries the Map object has. A set accessor function for size is undefined; you can not change this property.

MDN documentation

impl Map

pub fn entries(&self) -> Iterator

The entries() method returns a new Iterator object that contains the [key, value] pairs for each element in the Map object in insertion order.

MDN documentation

impl Map

pub fn keys(&self) -> Iterator

The keys() method returns a new Iterator object that contains the keys for each element in the Map object in insertion order.

MDN documentation

impl Map

pub fn values(&self) -> Iterator

The values() method returns a new Iterator object that contains the values for each element in the Map object in insertion order.

MDN documentation

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<JsValue> for Map

fn as_ref(&self) -> &JsValue

Performs the conversion.

impl AsRef<Map> for Map

fn as_ref(&self) -> &Map

Performs the conversion.

impl AsRef<Object> for Map

fn as_ref(&self) -> &Object

Performs the conversion.

impl Clone for Map

fn clone(&self) -> Map

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Map

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

Formats the value using the given formatter.

impl Deref for Map

type Target = Object

The resulting type after dereferencing.

fn deref(&self) -> &Object

Dereferences the value.

impl Eq for Map

impl From<JsValue> for Map

fn from(obj: JsValue) -> Map

Performs the conversion.

impl From<Map> for JsValue

fn from(obj: Map) -> JsValue

Performs the conversion.

impl From<Map> for Object

fn from(obj: Map) -> Object

Performs the conversion.

impl FromWasmAbi for Map

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 Map

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 Map

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 Map

fn instanceof(val: &JsValue) -> bool

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

pub fn is_type_of(val: &JsValue) -> bool

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

impl OptionFromWasmAbi for Map

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 Map

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 Map

fn none() -> Self::Abi

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

impl PartialEq<Map> for Map

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

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

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

This method tests for !=.

impl RefFromWasmAbi for Map

type Abi = <JsValue as RefFromWasmAbi>::Abi

The wasm ABI type references to Self are recovered from.

type Anchor = ManuallyDrop<Map>

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 Map

impl StructuralPartialEq for Map

impl WasmDescribe for Map

fn describe()