Struct Function 

pub struct Function<T: JsFunction = fn(JsValue, JsValue, JsValue, JsValue, JsValue, JsValue, JsValue, JsValue) -> JsValue> { /* private fields */ }

Function represents any generic Function in JS, by treating all arguments as JsValue.

It takes a generic parameter of phantom type fn (Arg1, ..., Argn) -> Ret which is used to type the JS function. For example, Function<fn () -> Number> represents a function taking no arguments that returns a number.

The 8 generic argument parameters (Arg1 through Arg8) are the argument types. Arguments not provided enable strict arity checking at compile time.

A void function is represented by fn (Arg) -> Undefined, and not the () unit type. This is because generics must be based on JS values in the JS generic type system.

The default without any parameters is as a void function - no arguments, Undefined return.

The default generic for Function is fn (JsValue, JsValue, ...) -> JsValue, representing any function, since all functions safely upcast into this function.

Arity Enforcement

It is not possible to use call4 or bind4 on a function that does not have at least 4 arguments — the compiler will reject this because only arguments that are not None support the trait bound for ErasableGeneric.

Examples

// A function taking no args, returning Number
let f: Function<Number> = get_some_fn();

// A function taking (String, Number) and returning Boolean
let f: Function<Boolean, String, Number> = get_some_fn();

## Upcasting

To pass a typed `Function` where a different generic Function is expected, `upcast()` may be used
to convert into any generic `Function` at zero cost with type-safety.

MDN documentation (https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function)

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<T> Function<T>

where T: JsFunction,

pub fn new_with_args_typed(args: &str, body: &str) -> Function<T>

where Function<T>: ErasableGenericOwn<Function<fn() -> JsValue>>,

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<T> Function<T>

where T: JsFunction,

pub fn new_no_args_typed(body: &str) -> Function<T>

where Function<T>: ErasableGenericOwn<Function<fn() -> JsValue>>,

The Function constructor creates a new Function object.

MDN documentation

impl<T> Function<T>

where T: JsFunction,

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

where <T as JsFunction>::Ret: ErasableGenericOwn<<fn() -> JsValue as JsFunction>::Ret>,

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<F, Ret> Function<F>

where Ret: JsGeneric, F: JsFunction<Ret = Ret>,

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

where Ret: ErasableGenericOwn<JsValue>,

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

Note: Use call() to get exact arity and also checked generic type casting.

MDN documentation

impl<Arg1, F, Ret> Function<F>

where Ret: JsGeneric, Arg1: JsGeneric, F: JsFunction<Ret = Ret> + JsFunction1<Arg1 = Arg1>,

pub fn call1(&self, context: &JsValue, arg1: &Arg1) -> Result<Ret, JsValue>

where Arg1: ErasableGenericBorrow<JsValue>, Ret: ErasableGenericOwn<JsValue>,

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

Note: Use call() to get exact arity and also checked generic type casting.

MDN documentation

impl<Arg1, Arg2, F, Ret> Function<F>

where Ret: JsGeneric, Arg1: JsGeneric, Arg2: JsGeneric, F: JsFunction<Ret = Ret> + JsFunction1<Arg1 = Arg1> + JsFunction2<Arg2 = Arg2>,

pub fn call2( &self, context: &JsValue, arg1: &Arg1, arg2: &Arg2, ) -> Result<Ret, JsValue>

where Arg1: ErasableGenericBorrow<JsValue>, Arg2: ErasableGenericBorrow<JsValue>, Ret: ErasableGenericOwn<JsValue>,

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

Note: Use call() to get exact arity and also checked generic type casting.

MDN documentation

impl<Arg1, Arg2, Arg3, F, Ret> Function<F>

where Ret: JsGeneric, Arg1: JsGeneric, Arg2: JsGeneric, Arg3: JsGeneric, F: JsFunction<Ret = Ret> + JsFunction3<Arg1 = Arg1, Arg2 = Arg2, Arg3 = Arg3>,

pub fn call3( &self, context: &JsValue, arg1: &Arg1, arg2: &Arg2, arg3: &Arg3, ) -> Result<Ret, JsValue>

where Arg1: ErasableGenericBorrow<JsValue>, Arg2: ErasableGenericBorrow<JsValue>, Arg3: ErasableGenericBorrow<JsValue>, Ret: ErasableGenericOwn<JsValue>,

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

Note: Use call() to get exact arity and also checked generic type casting.

MDN documentation

impl<Arg1, Arg2, Arg3, Arg4, F, Ret> Function<F>

where Ret: JsGeneric, Arg1: JsGeneric, Arg2: JsGeneric, Arg3: JsGeneric, Arg4: JsGeneric, F: JsFunction<Ret = Ret> + JsFunction4<Arg1 = Arg1, Arg2 = Arg2, Arg3 = Arg3, Arg4 = Arg4>,

pub fn call4( &self, context: &JsValue, arg1: &Arg1, arg2: &Arg2, arg3: &Arg3, arg4: &Arg4, ) -> Result<Ret, JsValue>

where Arg1: ErasableGenericBorrow<JsValue>, Arg2: ErasableGenericBorrow<JsValue>, Arg3: ErasableGenericBorrow<JsValue>, Arg4: ErasableGenericBorrow<JsValue>, Ret: ErasableGenericOwn<JsValue>,

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

Note: Use call() to get exact arity and also checked generic type casting.

MDN documentation

impl<Arg1, Arg2, Arg3, Arg4, Arg5, F, Ret> Function<F>

where Ret: JsGeneric, Arg1: JsGeneric, Arg2: JsGeneric, Arg3: JsGeneric, Arg4: JsGeneric, Arg5: JsGeneric, F: JsFunction<Ret = Ret> + JsFunction5<Arg1 = Arg1, Arg2 = Arg2, Arg3 = Arg3, Arg4 = Arg4, Arg5 = Arg5>,

pub fn call5( &self, context: &JsValue, arg1: &Arg1, arg2: &Arg2, arg3: &Arg3, arg4: &Arg4, arg5: &Arg5, ) -> Result<Ret, JsValue>

where Arg1: ErasableGenericBorrow<JsValue>, Arg2: ErasableGenericBorrow<JsValue>, Arg3: ErasableGenericBorrow<JsValue>, Arg4: ErasableGenericBorrow<JsValue>, Arg5: ErasableGenericBorrow<JsValue>, Ret: ErasableGenericOwn<JsValue>,

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

Note: Use call() to get exact arity and also checked generic type casting.

MDN documentation

impl<Arg1, Arg2, Arg3, Arg4, Arg5, Arg6, F, Ret> Function<F>

where Ret: JsGeneric, Arg1: JsGeneric, Arg2: JsGeneric, Arg3: JsGeneric, Arg4: JsGeneric, Arg5: JsGeneric, Arg6: JsGeneric, F: JsFunction<Ret = Ret> + JsFunction6<Arg1 = Arg1, Arg2 = Arg2, Arg3 = Arg3, Arg4 = Arg4, Arg5 = Arg5, Arg6 = Arg6>,

pub fn call6( &self, context: &JsValue, arg1: &Arg1, arg2: &Arg2, arg3: &Arg3, arg4: &Arg4, arg5: &Arg5, arg6: &Arg6, ) -> Result<Ret, JsValue>

where Arg1: ErasableGenericBorrow<JsValue>, Arg2: ErasableGenericBorrow<JsValue>, Arg3: ErasableGenericBorrow<JsValue>, Arg4: ErasableGenericBorrow<JsValue>, Arg5: ErasableGenericBorrow<JsValue>, Arg6: ErasableGenericBorrow<JsValue>, Ret: ErasableGenericOwn<JsValue>,

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

Note: Use call() to get exact arity and also checked generic type casting.

MDN documentation

impl<Arg1, Arg2, Arg3, Arg4, Arg5, Arg6, Arg7, F, Ret> Function<F>

where Ret: JsGeneric, Arg1: JsGeneric, Arg2: JsGeneric, Arg3: JsGeneric, Arg4: JsGeneric, Arg5: JsGeneric, Arg6: JsGeneric, Arg7: JsGeneric, F: JsFunction<Ret = Ret> + JsFunction7<Arg1 = Arg1, Arg2 = Arg2, Arg3 = Arg3, Arg4 = Arg4, Arg5 = Arg5, Arg6 = Arg6, Arg7 = Arg7>,

pub fn call7( &self, context: &JsValue, arg1: &Arg1, arg2: &Arg2, arg3: &Arg3, arg4: &Arg4, arg5: &Arg5, arg6: &Arg6, arg7: &Arg7, ) -> Result<Ret, JsValue>

where Arg1: ErasableGenericBorrow<JsValue>, Arg2: ErasableGenericBorrow<JsValue>, Arg3: ErasableGenericBorrow<JsValue>, Arg4: ErasableGenericBorrow<JsValue>, Arg5: ErasableGenericBorrow<JsValue>, Arg6: ErasableGenericBorrow<JsValue>, Arg7: ErasableGenericBorrow<JsValue>, Ret: ErasableGenericOwn<JsValue>,

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

Note: Use call() to get exact arity and also checked generic type casting.

MDN documentation

impl<Arg1, Arg2, Arg3, Arg4, Arg5, Arg6, Arg7, Arg8, F, Ret> Function<F>

where Ret: JsGeneric, Arg1: JsGeneric, Arg2: JsGeneric, Arg3: JsGeneric, Arg4: JsGeneric, Arg5: JsGeneric, Arg6: JsGeneric, Arg7: JsGeneric, Arg8: JsGeneric, F: JsFunction8<Ret = Ret, Arg1 = Arg1, Arg2 = Arg2, Arg3 = Arg3, Arg4 = Arg4, Arg5 = Arg5, Arg6 = Arg6, Arg7 = Arg7, Arg8 = Arg8>,

pub fn call8( &self, context: &JsValue, arg1: &Arg1, arg2: &Arg2, arg3: &Arg3, arg4: &Arg4, arg5: &Arg5, arg6: &Arg6, arg7: &Arg7, arg8: &Arg8, ) -> Result<Ret, JsValue>

where Arg1: ErasableGenericBorrow<JsValue>, Arg2: ErasableGenericBorrow<JsValue>, Arg3: ErasableGenericBorrow<JsValue>, Arg4: ErasableGenericBorrow<JsValue>, Arg5: ErasableGenericBorrow<JsValue>, Arg6: ErasableGenericBorrow<JsValue>, Arg7: ErasableGenericBorrow<JsValue>, Arg8: ErasableGenericBorrow<JsValue>, Ret: ErasableGenericOwn<JsValue>,

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

Note: Use call() to get exact arity and also checked generic type casting.

MDN documentation

impl<Arg1, Arg2, Arg3, Arg4, Arg5, Arg6, Arg7, Arg8, F, Ret> Function<F>

where Ret: JsGeneric, Arg1: JsGeneric, Arg2: JsGeneric, Arg3: JsGeneric, Arg4: JsGeneric, Arg5: JsGeneric, Arg6: JsGeneric, Arg7: JsGeneric, Arg8: JsGeneric, F: JsFunction8<Ret = Ret, Arg1 = Arg1, Arg2 = Arg2, Arg3 = Arg3, Arg4 = Arg4, Arg5 = Arg5, Arg6 = Arg6, Arg7 = Arg7, Arg8 = Arg8>,

pub fn call9( &self, context: &JsValue, arg1: &Arg1, arg2: &Arg2, arg3: &Arg3, arg4: &Arg4, arg5: &Arg5, arg6: &Arg6, arg7: &Arg7, arg8: &Arg8, arg9: &JsValue, ) -> Result<Ret, JsValue>

where Arg1: ErasableGenericBorrow<JsValue>, Arg2: ErasableGenericBorrow<JsValue>, Arg3: ErasableGenericBorrow<JsValue>, Arg4: ErasableGenericBorrow<JsValue>, Arg5: ErasableGenericBorrow<JsValue>, Arg6: ErasableGenericBorrow<JsValue>, Arg7: ErasableGenericBorrow<JsValue>, Arg8: ErasableGenericBorrow<JsValue>, Ret: ErasableGenericOwn<JsValue>,

👎Deprecated

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

Note: Use call() to get exact arity and also checked generic type casting.

MDN documentation

impl<T> Function<T>

where T: JsFunction,

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

where Function<T>: ErasableGenericOwn<Function<fn() -> JsValue>>,

👎Deprecated: Use Function::bind0 instead.

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<T> Function<T>

where T: JsFunction,

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

where Function<T>: ErasableGenericOwn<Function<fn() -> JsValue>>,

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.

Note: See Function::bindn for arbitrary binding with function arity checking.

MDN documentation

impl<Arg1, F, Ret> Function<F>

where Ret: JsGeneric, Arg1: JsGeneric, F: JsFunction1<Ret = Ret, Arg1 = Arg1>,

pub fn bind1( &self, context: &JsValue, arg1: &Arg1, ) -> Function<<F as JsFunction1>::Bind1>

where Arg1: ErasableGenericBorrow<JsValue>, Function<<F as JsFunction1>::Bind1>: ErasableGenericOwn<Function<<fn(JsValue) -> JsValue as JsFunction1>::Bind1>>,

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.

Note: See Function::bindn for arbitrary binding with function arity checking.

MDN documentation

impl<Arg1, Arg2, F, Ret> Function<F>

where Ret: JsGeneric, Arg1: JsGeneric, Arg2: JsGeneric, F: JsFunction2<Ret = Ret, Arg1 = Arg1, Arg2 = Arg2>,

pub fn bind2( &self, context: &JsValue, arg1: &Arg1, arg2: &Arg2, ) -> Function<<F as JsFunction2>::Bind2>

where Arg1: ErasableGenericBorrow<JsValue>, Arg2: ErasableGenericBorrow<JsValue>, Function<<F as JsFunction2>::Bind2>: ErasableGenericOwn<Function<<fn(JsValue, JsValue) -> JsValue as JsFunction2>::Bind2>>,

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.

Note: See Function::bindn for arbitrary binding with function arity checking.

MDN documentation

impl<Arg1, Arg2, Arg3, F, Ret> Function<F>

where Ret: JsGeneric, Arg1: JsGeneric, Arg2: JsGeneric, Arg3: JsGeneric, F: JsFunction3<Ret = Ret, Arg1 = Arg1, Arg2 = Arg2, Arg3 = Arg3>,

pub fn bind3( &self, context: &JsValue, arg1: &Arg1, arg2: &Arg2, arg3: &Arg3, ) -> Function<<F as JsFunction3>::Bind3>

where Arg1: ErasableGenericBorrow<JsValue>, Arg2: ErasableGenericBorrow<JsValue>, Arg3: ErasableGenericBorrow<JsValue>, Function<<F as JsFunction3>::Bind3>: ErasableGenericOwn<Function<<fn(JsValue, JsValue, JsValue) -> JsValue as JsFunction3>::Bind3>>,

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.

Note: See Function::bindn for arbitrary binding with function arity checking.

MDN documentation

impl<Arg1, Arg2, Arg3, Arg4, F, Ret> Function<F>

where Ret: JsGeneric, Arg1: JsGeneric, Arg2: JsGeneric, Arg3: JsGeneric, Arg4: JsGeneric, F: JsFunction4<Ret = Ret, Arg1 = Arg1, Arg2 = Arg2, Arg3 = Arg3, Arg4 = Arg4>,

pub fn bind4( &self, context: &JsValue, arg1: &Arg1, arg2: &Arg2, arg3: &Arg3, arg4: &Arg4, ) -> Function<<F as JsFunction4>::Bind4>

where Arg1: ErasableGenericBorrow<JsValue>, Arg2: ErasableGenericBorrow<JsValue>, Arg3: ErasableGenericBorrow<JsValue>, Arg4: ErasableGenericBorrow<JsValue>, Function<<F as JsFunction4>::Bind4>: ErasableGenericOwn<Function<<fn(JsValue, JsValue, JsValue, JsValue) -> JsValue as JsFunction4>::Bind4>>,

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.

Note: See Function::bindn for arbitrary binding with function arity checking.

MDN documentation

impl<Arg1, Arg2, Arg3, Arg4, Arg5, F, Ret> Function<F>

where Ret: JsGeneric, Arg1: JsGeneric, Arg2: JsGeneric, Arg3: JsGeneric, Arg4: JsGeneric, Arg5: JsGeneric, F: JsFunction5<Ret = Ret, Arg1 = Arg1, Arg2 = Arg2, Arg3 = Arg3, Arg4 = Arg4, Arg5 = Arg5>,

pub fn bind5( &self, context: &JsValue, arg1: &Arg1, arg2: &Arg2, arg3: &Arg3, arg4: &Arg4, arg5: &Arg5, ) -> Function<<F as JsFunction5>::Bind5>

where Arg1: ErasableGenericBorrow<JsValue>, Arg2: ErasableGenericBorrow<JsValue>, Arg3: ErasableGenericBorrow<JsValue>, Arg4: ErasableGenericBorrow<JsValue>, Arg5: ErasableGenericBorrow<JsValue>, Function<<F as JsFunction5>::Bind5>: ErasableGenericOwn<Function<<fn(JsValue, JsValue, JsValue, JsValue, JsValue) -> JsValue as JsFunction5>::Bind5>>,

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.

Note: See Function::bindn for arbitrary binding with function arity checking.

MDN documentation

impl<Arg1, Arg2, Arg3, Arg4, Arg5, Arg6, F, Ret> Function<F>

where Ret: JsGeneric, Arg1: JsGeneric, Arg2: JsGeneric, Arg3: JsGeneric, Arg4: JsGeneric, Arg5: JsGeneric, Arg6: JsGeneric, F: JsFunction6<Ret = Ret, Arg1 = Arg1, Arg2 = Arg2, Arg3 = Arg3, Arg4 = Arg4, Arg5 = Arg5, Arg6 = Arg6>,

pub fn bind6( &self, context: &JsValue, arg1: &Arg1, arg2: &Arg2, arg3: &Arg3, arg4: &Arg4, arg5: &Arg5, arg6: &Arg6, ) -> Function<<F as JsFunction6>::Bind6>

where Arg1: ErasableGenericBorrow<JsValue>, Arg2: ErasableGenericBorrow<JsValue>, Arg3: ErasableGenericBorrow<JsValue>, Arg4: ErasableGenericBorrow<JsValue>, Arg5: ErasableGenericBorrow<JsValue>, Arg6: ErasableGenericBorrow<JsValue>, Function<<F as JsFunction6>::Bind6>: ErasableGenericOwn<Function<<fn(JsValue, JsValue, JsValue, JsValue, JsValue, JsValue) -> JsValue as JsFunction6>::Bind6>>,

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.

Note: See Function::bindn for arbitrary binding with function arity checking.

MDN documentation

impl<Arg1, Arg2, Arg3, Arg4, Arg5, Arg6, Arg7, F, Ret> Function<F>

where Ret: JsGeneric, Arg1: JsGeneric, Arg2: JsGeneric, Arg3: JsGeneric, Arg4: JsGeneric, Arg5: JsGeneric, Arg6: JsGeneric, Arg7: JsGeneric, F: JsFunction7<Ret = Ret, Arg1 = Arg1, Arg2 = Arg2, Arg3 = Arg3, Arg4 = Arg4, Arg5 = Arg5, Arg6 = Arg6, Arg7 = Arg7>,

pub fn bind7( &self, context: &JsValue, arg1: &Arg1, arg2: &Arg2, arg3: &Arg3, arg4: &Arg4, arg5: &Arg5, arg6: &Arg6, arg7: &Arg7, ) -> Function<<F as JsFunction7>::Bind7>

where Arg1: ErasableGenericBorrow<JsValue>, Arg2: ErasableGenericBorrow<JsValue>, Arg3: ErasableGenericBorrow<JsValue>, Arg4: ErasableGenericBorrow<JsValue>, Arg5: ErasableGenericBorrow<JsValue>, Arg6: ErasableGenericBorrow<JsValue>, Arg7: ErasableGenericBorrow<JsValue>, Function<<F as JsFunction7>::Bind7>: ErasableGenericOwn<Function<<fn(JsValue, JsValue, JsValue, JsValue, JsValue, JsValue, JsValue) -> JsValue as JsFunction7>::Bind7>>,

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.

Note: See Function::bindn for arbitrary binding with function arity checking.

MDN documentation

impl<Arg1, Arg2, Arg3, Arg4, Arg5, Arg6, Arg7, Arg8, F, Ret> Function<F>

where Ret: JsGeneric, Arg1: JsGeneric, Arg2: JsGeneric, Arg3: JsGeneric, Arg4: JsGeneric, Arg5: JsGeneric, Arg6: JsGeneric, Arg7: JsGeneric, Arg8: JsGeneric, F: JsFunction8<Ret = Ret, Arg1 = Arg1, Arg2 = Arg2, Arg3 = Arg3, Arg4 = Arg4, Arg5 = Arg5, Arg6 = Arg6, Arg7 = Arg7, Arg8 = Arg8>,

pub fn bind8( &self, context: &JsValue, arg1: &Arg1, arg2: &Arg2, arg3: &Arg3, arg4: &Arg4, arg5: &Arg5, arg6: &Arg6, arg7: &Arg7, arg8: &Arg8, ) -> Function<<F as JsFunction8>::Bind8>

where Arg1: ErasableGenericBorrow<JsValue>, Arg2: ErasableGenericBorrow<JsValue>, Arg3: ErasableGenericBorrow<JsValue>, Arg4: ErasableGenericBorrow<JsValue>, Arg5: ErasableGenericBorrow<JsValue>, Arg6: ErasableGenericBorrow<JsValue>, Arg7: ErasableGenericBorrow<JsValue>, Arg8: ErasableGenericBorrow<JsValue>, Function<<F as JsFunction8>::Bind8>: ErasableGenericOwn<Function<<fn(JsValue, JsValue, JsValue, JsValue, JsValue, JsValue, JsValue, JsValue) -> JsValue as JsFunction8>::Bind8>>,

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.

Note: See Function::bindn for arbitrary binding with function arity checking.

MDN documentation

impl<Arg1, Arg2, Arg3, Arg4, Arg5, Arg6, Arg7, Arg8, F, Ret> Function<F>

where Ret: JsGeneric, Arg1: JsGeneric, Arg2: JsGeneric, Arg3: JsGeneric, Arg4: JsGeneric, Arg5: JsGeneric, Arg6: JsGeneric, Arg7: JsGeneric, Arg8: JsGeneric, F: JsFunction8<Ret = Ret, Arg1 = Arg1, Arg2 = Arg2, Arg3 = Arg3, Arg4 = Arg4, Arg5 = Arg5, Arg6 = Arg6, Arg7 = Arg7, Arg8 = Arg8>,

pub fn bind9( &self, context: &JsValue, arg1: &Arg1, arg2: &Arg2, arg3: &Arg3, arg4: &Arg4, arg5: &Arg5, arg6: &Arg6, arg7: &Arg7, arg8: &Arg8, arg9: &JsValue, ) -> Function<fn() -> Ret>

where Arg1: ErasableGenericBorrow<JsValue>, Arg2: ErasableGenericBorrow<JsValue>, Arg3: ErasableGenericBorrow<JsValue>, Arg4: ErasableGenericBorrow<JsValue>, Arg5: ErasableGenericBorrow<JsValue>, Arg6: ErasableGenericBorrow<JsValue>, Arg7: ErasableGenericBorrow<JsValue>, Arg8: ErasableGenericBorrow<JsValue>, Function<fn() -> Ret>: ErasableGenericOwn<Function<fn() -> JsValue>>,

👎Deprecated

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.

Note: See Function::bindn for arbitrary binding with function arity checking.

MDN documentation

impl<T> Function<T>

where T: JsFunction,

pub fn length(&self) -> u32

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

MDN documentation

impl<T> Function<T>

where T: JsFunction,

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<T> Function<T>

where T: JsFunction,

pub fn to_string(&self) -> JsString

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

MDN documentation

impl<T: JsFunction> Function<T>

pub fn len(&self) -> usize

Get the static arity of this function type.

pub fn is_empty(&self) -> bool

Returns true if this is a zero-argument function.

impl<T: JsFunction> Function<T>

pub fn call<Args: JsArgs<T>>( &self, context: &JsValue, args: Args, ) -> Result<T::Ret, JsValue>

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

This method accepts a tuple of references matching the function’s argument types.

Example

// 0-arg function
let f: Function<fn() -> Number> = get_fn();
let result = f.call(&JsValue::NULL, ())?;

// 1-arg function (note trailing comma for 1-tuple)
let f: Function<fn(JsString) -> Number> = get_fn();
let result = f.call(&JsValue::NULL, (&name,))?;

// 2-arg function
let f: Function<fn(JsString, Boolean) -> Number> = get_fn();
let result = f.call(&JsValue::NULL, (&name, &flag))?;

MDN documentation

pub fn bindn<Args: JsArgs<T>>( &self, context: &JsValue, args: Args, ) -> Args::BindOutput

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.

This method accepts a tuple of references to bind.

Example

let f: Function<fn(JsString, Boolean) -> Number> = get_fn();

// Bind no args - same signature
let bound: Function<fn(JsString, Boolean) -> Number> = f.bind(&ctx, ());

// Bind one arg (use 1-tuple of references)
let bound: Function<fn(Boolean) -> Number> = f.bind(&ctx, (&my_string,));

// Bind two args - becomes 0-arg function
let bound: Function<fn() -> Number> = f.bind(&ctx, (&my_string, &my_bool));

MDN documentation

impl<F: JsFunction> Function<F>

pub fn closure_ref<'a, C>(closure: &'a ScopedClosure<'_, C>) -> &'a Self

where F: FunctionIntoClosure, C: WasmClosure + ?Sized, <F as FunctionIntoClosure>::ClosureTypeMut: UpcastFrom<<C as WasmClosure>::AsMut>,

Convert a borrowed ScopedClosure into a typed JavaScript Function reference.

The conversion is a direct type-safe conversion and upcast of a closure into its corresponding typed JavaScript Function, based on covariance and contravariance Upcast trait hierarchy.

For transferring ownership to JS, use Function::from_closure.

pub fn from_closure<C>(closure: ScopedClosure<'static, C>) -> Self

where F: FunctionIntoClosure, C: WasmClosure + ?Sized, <F as FunctionIntoClosure>::ClosureTypeMut: UpcastFrom<<C as WasmClosure>::AsMut>,

Convert a Rust closure into a typed JavaScript Function.

This function releases ownership of the closure to JS, and provides an owned function handle for the same closure.

The conversion is a direct type-safe conversion and upcast of a closure into its corresponding typed JavaScript Function, based on covariance and contravariance Upcast trait hierarchy.

This method is only supported for static closures which do not have borrowed lifetime data, and thus can be released into JS.

For borrowed closures, which cannot cede ownership to JS, instead use Function::closure_ref.

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

👎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<T: JsFunction> AsRef<Function<T>> for Function<T>

fn as_ref(&self) -> &Function<T>

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

impl<T: JsFunction> AsRef<JsValue> for Function<T>

fn as_ref(&self) -> &JsValue

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

impl<T: JsFunction> AsRef<Object> for Function<T>

fn as_ref(&self) -> &Object

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

impl<T: Clone + JsFunction> Clone for Function<T>

fn clone(&self) -> Function<T>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<T: Debug + JsFunction> Debug for Function<T>

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

Formats the value using the given formatter.

impl Default for Function

Available on crate feature unsafe-eval only.

fn default() -> Self

Returns the “default value” for a type.

impl<T: JsFunction> Deref for Function<T>

type Target = Object

The resulting type after dereferencing.

fn deref(&self) -> &Object

Dereferences the value.

impl<T: JsFunction> ErasableGeneric for Function<T>

type Repr = JsValue

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

impl<T: JsFunction> From<Function<T>> for JsValue

fn from(obj: Function<T>) -> JsValue

Converts to this type from the input type.

impl<T: JsFunction> From<Function<T>> for Object

fn from(obj: Function<T>) -> Object

Converts to this type from the input type.

impl From<JsValue> for Function

fn from(obj: JsValue) -> Self

Converts to this type from the input type.

impl<T: JsFunction> FromWasmAbi for Function<T>

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, T: JsFunction> IntoWasmAbi for &'a Function<T>

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<T: JsFunction> IntoWasmAbi for Function<T>

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<T: JsFunction> JsCast for Function<T>

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<T: JsFunction> LongRefFromWasmAbi for Function<T>

type Abi = <JsValue as LongRefFromWasmAbi>::Abi

Same as RefFromWasmAbi::Abi

type Anchor = Function<T>

Same as RefFromWasmAbi::Anchor

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

Same as RefFromWasmAbi::ref_from_abi

impl<T: JsFunction> OptionFromWasmAbi for Function<T>

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, T: JsFunction> OptionIntoWasmAbi for &'a Function<T>

fn none() -> Self::Abi

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

impl<T: JsFunction> OptionIntoWasmAbi for Function<T>

fn none() -> Self::Abi

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

impl<T: PartialEq + JsFunction> PartialEq for Function<T>

fn eq(&self, other: &Function<T>) -> 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<T: JsFunction> Promising for Function<T>

type Resolution = Function<T>

The type that this value resolves to.

impl<T: JsFunction> RefFromWasmAbi for Function<T>

type Abi = <JsValue as RefFromWasmAbi>::Abi

The Wasm ABI type references to Self are recovered from.

type Anchor = ManuallyDrop<Function<T>>

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<T: JsFunction> WasmDescribe for Function<T>

fn describe()

impl<T: Eq + JsFunction> Eq for Function<T>

impl<T: JsFunction> StructuralPartialEq for Function<T>

impl<T: JsFunction, U> UpcastFrom<Function<T>> for Function<U>

where U: UpcastFrom<T> + JsFunction,

impl<T: JsFunction> UpcastFrom<Function<T>> for JsOption<JsValue>

impl<T: JsFunction> UpcastFrom<Function<T>> for JsOption<Object>

impl<T: JsFunction> UpcastFrom<Function<T>> for JsValue

impl<T: JsFunction> UpcastFrom<Function<T>> for Object