JavaScriptKit Documentation

Class JSFunction 

public class JSFunction: JSObject

JSFunction represents a function in JavaScript and supports new object instantiation. This type can be callable as a function using callAsFunction.

e.g.

let alert: JSFunction = JSObject.global.alert.function!
// Call `JSFunction` as a function
alert("Hello, world")
%19 JSFunction JSFunction JSObject JSObject JSFunction->JSObject

Superclass

JSObject

JSObject represents an object in JavaScript and supports dynamic member lookup. Any member access like object.foo will dynamically request the JavaScript and Swift runtime bridge library for a member with the specified name in this object.

Properties

`throws` 

public var `throws`: JSThrowingFunction

A modifier to call this function as a throwing function

function validateAge(age) {
  if (age < 0) {
    throw new Error("Invalid age");
  }
}

let validateAge = JSObject.global.validateAge.function!
try validateAge.throws(20)

js​Value 

override public var jsValue: JSValue

Methods

call​AsFunction(this:​arguments:​) 

@discardableResult
    public func callAsFunction(this: JSObject, arguments: [ConvertibleToJSValue]) -> JSValue

Call this function with given arguments and binding given this as context.

Parameters

this JSObject

The value to be passed as the this parameter to this function.
arguments [Convertible​ToJSValue]

Arguments to be passed to this function.

Returns

The result of this call.

call​AsFunction(arguments:​) 

@discardableResult
    public func callAsFunction(arguments: [ConvertibleToJSValue]) -> JSValue

Call this function with given arguments.

Parameters

arguments [Convertible​ToJSValue]

Arguments to be passed to this function.

Returns

The result of this call.

call​AsFunction(this:​_:​) 

@discardableResult
    public func callAsFunction(this: JSObject, _ arguments: ConvertibleToJSValue...) -> JSValue

A variadic arguments version of callAsFunction.

call​AsFunction(_:​) 

@discardableResult
    public func callAsFunction(_ arguments: ConvertibleToJSValue...) -> JSValue

A variadic arguments version of callAsFunction.

new(arguments:​) 

public func new(arguments: [ConvertibleToJSValue]) -> JSObject

Instantiate an object from this function as a constructor.

Guaranteed to return an object because either:

  • a. the constructor explicitly returns an object, or

  • b. the constructor returns nothing, which causes JS to return the this value, or

  • c. the constructor returns undefined, null or a non-object, in which case JS also returns this.

Parameters

arguments [Convertible​ToJSValue]

Arguments to be passed to this constructor function.

Returns

A new instance of this constructor.

new(_:​) 

public func new(_ arguments: ConvertibleToJSValue...) -> JSObject

A variadic arguments version of new.

from(_:​) 

@available(*, unavailable, message: "Please use JSClosure instead")
    public static func from(_: @escaping ([JSValue]) -> JSValue) -> JSFunction

construct(from:​) 

override public class func construct(from value: JSValue) -> Self?