Struct Map 

pub struct Map<K = JsValue, V = JsValue> { /* private fields */ }

Implementations

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.

Note: Consider using Map::new_typed for typing support.

MDN documentation

impl<K, V> Map<K, V>

pub fn new_typed() -> Map<K, V>

where Map<K, V>: ErasableGenericOwn<Map<JsValue, JsValue>>,

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<K, V> Map<K, V>

pub fn new_from_entries<I>(entries: &I) -> Map<K, V>

where I: Iterable<Item = ArrayTuple<(K, V)>> + ErasableGenericBorrow<JsValue>, Map<K, V>: ErasableGenericOwn<Map<JsValue, JsValue>>,

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<K, V> Map<K, V>

pub fn clear(&self)

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

MDN documentation

impl<K, V> Map<K, V>

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

where K: ErasableGenericBorrow<JsValue>,

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

MDN documentation

impl<K, V> Map<K, V>

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

where dyn FnMut(V, K): ErasableGenericBorrowMut<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<K, V> Map<K, V>

pub fn try_for_each<'a>( &self, callback: &ImmediateClosure<'a, dyn FnMut(V, K) -> Result<(), JsError> + 'a>, ) -> Result<(), JsValue>

where ImmediateClosure<'a, dyn FnMut(V, K) -> Result<(), JsError> + 'a>: ErasableGenericBorrow<ImmediateClosure<'static, dyn FnMut(JsValue, JsValue) -> Result<(), JsError> + 'static>>,

The forEach() method executes a provided function once per each key/value pair in the Map object, in insertion order. (Fallible variation) 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...
})

Note: Consider using Map::try_for_each if the callback might throw an error.

MDN documentation

impl<K, V> Map<K, V>

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

where K: ErasableGenericBorrow<JsValue>, V: ErasableGenericOwn<JsValue>,

The get() method returns a specified element from a Map object. Returns undefined if the key is not found.

Note: Consider using Map::get_checked to get an Option<V> instead.

MDN documentation

impl<K, V> Map<K, V>

pub fn get_checked(&self, key: &K) -> Option<V>

where K: ErasableGenericBorrow<JsValue>, Option<V>: ErasableGenericOwn<Option<JsValue>>,

The get() method returns a specified element from a Map object. Returns None if the key is not found.

MDN documentation

impl<K, V> Map<K, V>

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

where K: ErasableGenericBorrow<JsValue>,

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

MDN documentation

impl<K, V> Map<K, V>

pub fn set(&self, key: &K, value: &V) -> Map<K, V>

where K: ErasableGenericBorrow<JsValue>, V: ErasableGenericBorrow<JsValue>, Map<K, V>: ErasableGenericOwn<Map<JsValue, JsValue>>,

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

MDN documentation

impl<K, V> Map<K, V>

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<K, V> Map<K, V>

where V: FromWasmAbi,

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<K, V> Map<K, V>

where K: JsGeneric, V: FromWasmAbi + JsGeneric,

pub fn entries_typed(&self) -> Iterator<ArrayTuple<(K, V)>>

where Iterator<ArrayTuple<(K, V)>>: ErasableGenericOwn<Iterator<ArrayTuple<(JsValue, JsValue)>>>,

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<K, V> Map<K, V>

where K: FromWasmAbi, V: FromWasmAbi,

pub fn keys(&self) -> Iterator<K>

where Iterator<K>: ErasableGenericOwn<Iterator<JsValue>>,

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<K, V> Map<K, V>

where V: FromWasmAbi,

pub fn values(&self) -> Iterator<V>

where Iterator<V>: ErasableGenericOwn<Iterator<JsValue>>,

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

👎Deprecated: Use Object::hasOwn instead.

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 to_js_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_null_or_undefined(&self) -> bool

Tests whether this JS value is null or 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_array(&self) -> bool

Tests whether this JS value is an instance of Array.

pub fn is_function(&self) -> bool

Tests whether the type of this JS value is function.

pub fn is_bigint(&self) -> bool

Tests whether the type of this JS value is bigint.

pub fn js_typeof(&self) -> JsValue

Applies the unary typeof JS operator on a JsValue.

MDN documentation

pub fn js_in(&self, obj: &JsValue) -> bool

Applies the binary in JS operator on the two JsValues.

MDN documentation

pub fn is_truthy(&self) -> bool

Tests whether the value is “truthy”.

pub fn is_falsy(&self) -> bool

Tests whether the value is “falsy”.

pub fn loose_eq(&self, other: &JsValue) -> bool

Compare two JsValues for equality, using the == operator in JS.

MDN documentation

pub fn bit_not(&self) -> JsValue

Applies the unary ~ JS operator on a JsValue.

MDN documentation

pub fn unsigned_shr(&self, rhs: &JsValue) -> u32

Applies the binary >>> JS operator on the two JsValues.

MDN documentation

pub fn checked_div(&self, rhs: &JsValue) -> JsValue

Applies the binary / JS operator on two JsValues, catching and returning any RangeError thrown.

MDN documentation

pub fn pow(&self, rhs: &JsValue) -> JsValue

Applies the binary ** JS operator on the two JsValues.

MDN documentation

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

Applies the binary < JS operator on the two JsValues.

MDN documentation

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

Applies the binary <= JS operator on the two JsValues.

MDN documentation

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

Applies the binary >= JS operator on the two JsValues.

MDN documentation

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

Applies the binary > JS operator on the two JsValues.

MDN documentation

pub fn unchecked_into_f64(&self) -> f64

Applies the unary + JS operator on a JsValue. Can throw.

MDN documentation

Trait Implementations

impl<K, V> AsRef<JsValue> for Map<K, V>

fn as_ref(&self) -> &JsValue

Converts this type into a shared reference of the (usually inferred) input type.

impl<K, V> AsRef<Map<K, V>> for Map<K, V>

fn as_ref(&self) -> &Map<K, V>

Converts this type into a shared reference of the (usually inferred) input type.

impl<K, V> AsRef<Object> for Map<K, V>

fn as_ref(&self) -> &Object

Converts this type into a shared reference of the (usually inferred) input type.

impl<K: Clone, V: Clone> Clone for Map<K, V>

fn clone(&self) -> Map<K, V>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<K: Debug, V: Debug> Debug for Map<K, V>

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

Formats the value using the given formatter.

impl Default for Map<JsValue, JsValue>

fn default() -> Self

Returns the “default value” for a type.

impl<K, V> Deref for Map<K, V>

type Target = Object

The resulting type after dereferencing.

fn deref(&self) -> &Object

Dereferences the value.

impl<K, V> ErasableGeneric for Map<K, V>

type Repr = JsValue

The singular concrete type that all generic variants can be transmuted on

impl From<JsValue> for Map

fn from(obj: JsValue) -> Self

Converts to this type from the input type.

impl<K, V> From<Map<K, V>> for JsValue

fn from(obj: Map<K, V>) -> JsValue

Converts to this type from the input type.

impl<K, V> From<Map<K, V>> for Object

fn from(obj: Map<K, V>) -> Object

Converts to this type from the input type.

impl<K, V> FromWasmAbi for Map<K, V>

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<'a, K, V> IntoWasmAbi for &'a Map<K, V>

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<K, V> IntoWasmAbi for Map<K, V>

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<K, V> Iterable for Map<K, V>

type Item = ArrayTuple<(K, V)>

The type of values yielded by this iterable.

impl<K, V> JsCast for Map<K, V>

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.

fn has_type<T>(&self) -> bool

where T: JsCast,

Test whether this JS value has a type T.

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.

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.

fn unchecked_into<T>(self) -> T

where T: JsCast,

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

fn unchecked_ref<T>(&self) -> &T

where T: JsCast,

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

fn is_instance_of<T>(&self) -> bool

where T: JsCast,

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

fn is_type_of(val: &JsValue) -> bool

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

impl<K, V> LongRefFromWasmAbi for Map<K, V>

type Abi = <JsValue as LongRefFromWasmAbi>::Abi

Same as RefFromWasmAbi::Abi

type Anchor = Map<K, V>

Same as RefFromWasmAbi::Anchor

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

Same as RefFromWasmAbi::ref_from_abi

impl<K, V> OptionFromWasmAbi for Map<K, V>

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<'a, K, V> OptionIntoWasmAbi for &'a Map<K, V>

fn none() -> Self::Abi

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

impl<K, V> OptionIntoWasmAbi for Map<K, V>

fn none() -> Self::Abi

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

impl<K: PartialEq, V: PartialEq> PartialEq for Map<K, V>

fn eq(&self, other: &Map<K, V>) -> 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<K, V> Promising for Map<K, V>

type Resolution = Map<K, V>

The type that this value resolves to.

impl<K, V> RefFromWasmAbi for Map<K, V>

type Abi = <JsValue as RefFromWasmAbi>::Abi

The Wasm ABI type references to Self are recovered from.

type Anchor = ManuallyDrop<Map<K, V>>

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<K, V> WasmDescribe for Map<K, V>

fn describe()

impl<K: Eq, V: Eq> Eq for Map<K, V>

impl<K, V> StructuralPartialEq for Map<K, V>

impl<K, V, __UpcastTarget0, __UpcastTarget1> UpcastFrom<Map<K, V>> for JsOption<Map<__UpcastTarget0, __UpcastTarget1>>

where __UpcastTarget0: UpcastFrom<K>, __UpcastTarget1: UpcastFrom<V>,

impl<K, V> UpcastFrom<Map<K, V>> for JsOption<Object>

impl<K, V> UpcastFrom<Map<K, V>> for JsValue

impl<K, V, __UpcastTarget0, __UpcastTarget1> UpcastFrom<Map<K, V>> for Map<__UpcastTarget0, __UpcastTarget1>

where __UpcastTarget0: UpcastFrom<K>, __UpcastTarget1: UpcastFrom<V>,

impl<K, V> UpcastFrom<Map<K, V>> for Object