Struct js_sys::Function

#[repr(transparent)]
pub struct Function { /* private fields */ }

Implementations

impl Function

pub fn new_with_args(args: &str, body: &str) -> Function

The Function constructor creates a new Function object. Calling the constructor directly can create functions dynamically, but suffers from security and similar (but far less significant) performance issues similar to eval. However, unlike eval, the Function constructor allows executing code in the global scope, prompting better programming habits and allowing for more efficient code minification.

MDN documentation

impl Function

pub fn new_no_args(body: &str) -> Function

The Function constructor creates a new Function object. Calling the constructor directly can create functions dynamically, but suffers from security and similar (but far less significant) performance issues similar to eval. However, unlike eval, the Function constructor allows executing code in the global scope, prompting better programming habits and allowing for more efficient code minification.

MDN documentation

impl Function

pub fn apply(&self, context: &JsValue, args: &Array) -> Result<JsValue, JsValue>

The apply() method calls a function with a given this value, and arguments provided as an array (or an array-like object).

MDN documentation

impl Function

pub fn call0(&self, context: &JsValue) -> Result<JsValue, JsValue>

The call() method calls a function with a given this value and arguments provided individually.

MDN documentation

impl Function

pub fn call1(
    &self,
    context: &JsValue,
    arg1: &JsValue
) -> Result<JsValue, JsValue>

The call() method calls a function with a given this value and arguments provided individually.

MDN documentation

impl Function

pub fn call2(
    &self,
    context: &JsValue,
    arg1: &JsValue,
    arg2: &JsValue
) -> Result<JsValue, JsValue>

The call() method calls a function with a given this value and arguments provided individually.

MDN documentation

impl Function

pub fn call3(
    &self,
    context: &JsValue,
    arg1: &JsValue,
    arg2: &JsValue,
    arg3: &JsValue
) -> Result<JsValue, JsValue>

The call() method calls a function with a given this value and arguments provided individually.

MDN documentation

impl Function

pub fn bind(&self, context: &JsValue) -> Function

The bind() method creates a new function that, when called, has its this keyword set to the provided value, with a given sequence of arguments preceding any provided when the new function is called.

MDN documentation

impl Function

pub fn bind0(&self, context: &JsValue) -> Function

The bind() method creates a new function that, when called, has its this keyword set to the provided value, with a given sequence of arguments preceding any provided when the new function is called.

MDN documentation

impl Function

pub fn bind1(&self, context: &JsValue, arg1: &JsValue) -> Function

The bind() method creates a new function that, when called, has its this keyword set to the provided value, with a given sequence of arguments preceding any provided when the new function is called.

MDN documentation

impl Function

pub fn bind2(
    &self,
    context: &JsValue,
    arg1: &JsValue,
    arg2: &JsValue
) -> Function

The bind() method creates a new function that, when called, has its this keyword set to the provided value, with a given sequence of arguments preceding any provided when the new function is called.

MDN documentation

impl Function

pub fn bind3(
    &self,
    context: &JsValue,
    arg1: &JsValue,
    arg2: &JsValue,
    arg3: &JsValue
) -> Function

The bind() method creates a new function that, when called, has its this keyword set to the provided value, with a given sequence of arguments preceding any provided when the new function is called.

MDN documentation

impl Function

pub fn length(&self) -> u32

The length property indicates the number of arguments expected by the function.

MDN documentation

impl Function

pub fn name(&self) -> JsString

A Function object’s read-only name property indicates the function’s name as specified when it was created or “anonymous” for functions created anonymously.

MDN documentation

impl Function

pub fn to_string(&self) -> JsString

The toString() method returns a string representing the source code of the function.

MDN documentation

impl Function

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

👎 Deprecated:

recommended to use dyn_ref instead which is now equivalent

Returns the Function value of this JS value if it’s an instance of a function.

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

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<Function> for Function

fn as_ref(&self) -> &Function

Performs the conversion.

impl AsRef<JsValue> for Function

fn as_ref(&self) -> &JsValue

Performs the conversion.

impl AsRef<Object> for Function

fn as_ref(&self) -> &Object

Performs the conversion.

impl Clone for Function

fn clone(&self) -> Function

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Function

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

Formats the value using the given formatter.

impl Default for Function

fn default() -> Self

Returns the “default value” for a type.

impl Deref for Function

type Target = Object

The resulting type after dereferencing.

fn deref(&self) -> &Object

Dereferences the value.

impl From<Function> for JsValue

fn from(obj: Function) -> JsValue

Performs the conversion.

impl From<Function> for Object

fn from(obj: Function) -> Object

Performs the conversion.

impl From<JsValue> for Function

fn from(obj: JsValue) -> Function

Performs the conversion.

impl FromWasmAbi for Function

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 Function

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 Function

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 Function

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.

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.

impl OptionFromWasmAbi for Function

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 Function

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 Function

fn none() -> Self::Abi

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

impl PartialEq<Function> for Function

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

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

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

This method tests for !=.

impl RefFromWasmAbi for Function

type Abi = <JsValue as RefFromWasmAbi>::Abi

The wasm ABI type references to Self are recovered from.

type Anchor = ManuallyDrop<Function>

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 WasmDescribe for Function

fn describe()

impl Eq for Function

impl StructuralEq for Function

impl StructuralPartialEq for Function