js

package
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 Go to latest Published: Jun 23, 2020 License: Apache-2.0 Imports: 6 Imported by: 0

Documentation

Overview

Package js provides additional functionality on top of syscall/js package for WASM.

Index

Constants

View Source 
const (
	TypeObject   = js.TypeObject
	TypeFunction = js.TypeFunction
)

Variables

This section is empty.

Functions

func NewError 

func NewError(e Wrapper) error

NewError creates a new Go error from JS error value.

func Set 

func Set(name string, v interface{})

Set is a shorthand for Global().Set().

Types

type Arr 

type Arr = []interface{}

Arr is an alias for []interface{}.

type Callback deprecated 

type Callback = Func

Callback is a wrapped Go function to be called by JavaScript.

Deprecated: use Func

type CallbackGroup deprecated 

type CallbackGroup = FuncGroup

CallbackGroup is a list of Go functions attached to an object.

Deprecated: use FuncGroup

type Error 

type Error = js.Error

Error is an alias for syscall/js.Error.

type Func 

type Func = js.Func

Func is a wrapped Go function to be called by JavaScript.

func AsyncCallbackOf 

func AsyncCallbackOf(fnc func(v []Value)) Func

AsyncCallbackOf returns a wrapped callback function.

Invoking the callback in JavaScript will queue the Go function fn for execution. This execution happens asynchronously.

Callback.Release must be called to free up resources when the callback will not be used any more.

func CallbackOf 

func CallbackOf(fnc func(v []Value)) Func

CallbackOf returns a wrapped callback function.

Invoking the callback in JavaScript will queue the Go function fn for execution. This execution happens asynchronously on a special goroutine that handles all callbacks and preserves the order in which the callbacks got called. As a consequence, if one callback blocks this goroutine, other callbacks will not be processed. A blocking callback should therefore explicitly start a new goroutine.

Callback.Release must be called to free up resources when the callback will not be used any more.

func FuncOf 

func FuncOf(fnc func(this Value, args []Value) interface{}) Func

FuncOf returns a wrapped function.

Invoking the JavaScript function will synchronously call the Go function fn with the value of JavaScript's "this" keyword and the arguments of the invocation. The return value of the invocation is the result of the Go function mapped back to JavaScript according to ValueOf.

A wrapped function triggered during a call from Go to JavaScript gets executed on the same goroutine. A wrapped function triggered by JavaScript's event loop gets executed on an extra goroutine. Blocking operations in the wrapped function will block the event loop. As a consequence, if one wrapped function blocks, other wrapped funcs will not be processed. A blocking function should therefore explicitly start a new goroutine.

Func.Release must be called to free up resources when the function will not be used any more.

func NewCallback deprecated 

func NewCallback(fnc func(v []Value)) Func

NewCallback returns a wrapped callback function.

Invoking the callback in JavaScript will queue the Go function fn for execution. This execution happens asynchronously on a special goroutine that handles all callbacks and preserves the order in which the callbacks got called. As a consequence, if one callback blocks this goroutine, other callbacks will not be processed. A blocking callback should therefore explicitly start a new goroutine.

Callback.Release must be called to free up resources when the callback will not be used any more.

Deprecated: use CallbackOf

func NewCallbackAsync deprecated 

func NewCallbackAsync(fnc func(v []Value)) Func

NewCallbackAsync returns a wrapped callback function.

Invoking the callback in JavaScript will queue the Go function fn for execution. This execution happens asynchronously.

Callback.Release must be called to free up resources when the callback will not be used any more.

Deprecated: AsyncCallbackOf

func NewEventCallback 

func NewEventCallback(fnc func(v Value)) Func

NewEventCallback is a shorthand for NewEventCallbackFlags with default flags.

func NewFunc deprecated 

func NewFunc(fnc func(this Value, args []Value) interface{}) Func

NewFunc returns a wrapped function that will be executed synchronously.

Deprecated: use FuncOf

type FuncGroup 

type FuncGroup struct {
	// contains filtered or unexported fields
}

FuncGroup is a list of Go functions attached to an object.

func (*FuncGroup) Add 

func (g *FuncGroup) Add(cb Func)

func (*FuncGroup) AddEventListener 

func (g *FuncGroup) AddEventListener(event string, fnc func(Value))

func (*FuncGroup) ErrorEvent 

func (g *FuncGroup) ErrorEvent(fnc func(error))

func (*FuncGroup) ErrorEventChan 

func (g *FuncGroup) ErrorEventChan() <-chan error

func (*FuncGroup) OneTimeEvent 

func (g *FuncGroup) OneTimeEvent(event string, fnc func(Value))

func (*FuncGroup) OneTimeEventChan 

func (g *FuncGroup) OneTimeEventChan(event string) <-chan Value

func (*FuncGroup) OneTimeTrigger 

func (g *FuncGroup) OneTimeTrigger(event string) <-chan struct{}

func (*FuncGroup) Release 

func (g *FuncGroup) Release()

func (*FuncGroup) Set 

func (g *FuncGroup) Set(name string, fnc func([]Value))

type JSRef deprecated 

type JSRef = Wrapper

JSRef is a common interface for object that are backed by a JS object.

Deprecated: see Wrapper

type Obj 

type Obj = map[string]interface{}

Obj is an alias for map[string]interface{}.

type Promise 

type Promise struct {
	// contains filtered or unexported fields
}

Promise represents a JavaScript Promise.

func (*Promise) Await 

func (p *Promise) Await() ([]Value, error)

Await for the promise to resolve.

func (*Promise) AwaitContext 

func (p *Promise) AwaitContext(ctx context.Context) ([]Value, error)

AwaitContext for the promise to resolve or context to be canceled.

func (*Promise) JSValue 

func (p *Promise) JSValue() Ref

JSValue implements Wrapper interface.

type Ref 

type Ref = js.Value

Ref is an alias for syscall/js.Value.

type Type 

type Type = js.Type

Type is a type name of a JS value, as returned by "typeof".

type Value 

type Value struct {
	Ref
}

Value is a convenience wrapper for syscall/js.Value. It provides some additional functionality, while storing no additional state. Its safe to instantiate Value directly, by wrapping syscall/js.Value.

func Array 

func Array() Value

Array returns an Array JS class.

func Call 

func Call(name string, args ...interface{}) Value

Call is a shorthand for Global().Call().

func Class 

func Class(class string) Value

Class searches for a class in global scope. It caches results, so the lookup should be faster than calling Get.

func Get 

func Get(name string, path ...string) Value

Get is a shorthand for Global().Get().

func NativeFuncOf 

func NativeFuncOf(argsAndCode ...string) Value

NativeFuncOf creates a function from a JS code string.

Example: 

NativeFuncOf("a", "b", "return a+b").Call(a, b)

func New 

func New(class string, args ...interface{}) Value

New searches for a class in global scope and creates a new instance of that class.

func NewArray 

func NewArray() Value

NewArray creates an empty JS array.

func NewFuncJS deprecated 

func NewFuncJS(argsAndCode ...string) Value

NewFuncJS creates a function from a JS code string.

Deprecated: use RawFuncOf

Example: 

NativeFuncOf("a", "b", "return a+b").Call(a, b)

func NewObject 

func NewObject() Value

NewObject creates an empty JS object.

func NewPromise 

func NewPromise(fnc func() ([]interface{}, error)) Value

NewPromise runs a given function asynchronously by converting it to JavaScript promise. Promise will be resolved if functions returns a nil error and will be rejected otherwise.

func Object 

func Object() Value

Object returns an Object JS class.

func ValueOf 

func ValueOf(o interface{}) Value

ValueOf returns x as a JavaScript value: 

| Go                     | JavaScript             |
| ---------------------- | ---------------------- |
| js.Value               | [its value]            |
| js.TypedArray          | typed array            |
| js.Callback            | function               |
| nil                    | null                   |
| bool                   | boolean                |
| integers and floats    | number                 |
| string                 | string                 |
| []interface{}          | new array              |
| map[string]interface{} | new object             |

func (Value) Await 

func (v Value) Await() ([]Value, error)

Await wait for the promise to be resolved or rejected. A shorthand for calling Await on the promise returned by Promised.

func (Value) Call 

func (v Value) Call(name string, args ...interface{}) Value

Call does a JavaScript call to the method m of value v with the given arguments. It panics if v has no method m. The arguments get mapped to JavaScript values according to the ValueOf function.

func (Value) Get 

func (v Value) Get(name string, path ...string) Value

Get returns the JS property by name.

func (Value) Index 

func (v Value) Index(i int) Value

Index returns JS index i of value v.

func (Value) InstanceOf 

func (v Value) InstanceOf(class Value) bool

InstanceOf reports whether v is an instance of type t according to JavaScript's instanceof operator.

func (Value) InstanceOfClass 

func (v Value) InstanceOfClass(class string) bool

InstanceOfClass reports whether v is an instance of named type according to JavaScript's instanceof operator.

func (Value) Invoke 

func (v Value) Invoke(args ...interface{}) Value

Invoke does a JavaScript call of the value v with the given arguments. It panics if v is not a function. The arguments get mapped to JavaScript values according to the ValueOf function.

func (Value) IsNull 

func (v Value) IsNull() bool

IsNull checks if a value represents JS null object.

func (Value) IsUndefined 

func (v Value) IsUndefined() bool

IsUndefined checks if a value represents JS undefined object.

func (Value) JSRef deprecated 

func (v Value) JSRef() Ref

JSRef returns a JS object reference as defined by syscall/js.

Deprecated: use JSValue

func (Value) JSValue 

func (v Value) JSValue() Ref

JSValue implements Wrapper interface.

func (Value) MarshalJSON 

func (v Value) MarshalJSON() ([]byte, error)

MarshalJSON encodes a value into JSON by using native JavaScript function (JSON.stringify).

func (Value) New 

func (v Value) New(args ...interface{}) Value

New uses JavaScript's "new" operator with value v as constructor and the given arguments. It panics if v is not a function. The arguments get mapped to JavaScript values according to the ValueOf function.

func (Value) NewCallbackGroup deprecated 

func (v Value) NewCallbackGroup() *FuncGroup

NewCallbackGroup creates a new function group on this object.

Deprecated: use NewFuncGroup

func (Value) NewFuncGroup 

func (v Value) NewFuncGroup() *FuncGroup

NewFuncGroup creates a new function group on this object.

func (Value) Promised 

func (v Value) Promised() *Promise

Promised returns converts the value into a Promise.

func (Value) Set 

func (v Value) Set(name string, val interface{})

Set sets the JS property to ValueOf(x).

func (Value) SetIndex 

func (v Value) SetIndex(i int, val interface{})

SetIndex sets the JavaScript index i of value v to ValueOf(x).

func (Value) Slice 

func (v Value) Slice() []Value

Slice converts JS Array to a Go slice of JS values.

func (Value) String 

func (v Value) String() string

String converts a value to a string.

func (Value) Type 

func (v Value) Type() Type

Type is an analog for JS "typeof" operator.

func (*Value) UnmarshalJSON 

func (v *Value) UnmarshalJSON(p []byte) (err error)

UnmarshalJSON decodes a value from JSON by using native JavaScript functions (JSON.parse).

func (Value) Valid 

func (v Value) Valid() bool

Valid checks if object is defined and not null.

type Wrapper 

type Wrapper interface {
	// JSValue returns a JavaScript value associated with an object.
	JSValue() js.Value
}

Wrapper is implemented by types that are backed by a JavaScript value.

Source Files

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