jsre

Documentation

Overview

Package jsre provides an execution environment for JavaScript.

JSRE is a generic JS runtime environment embedding the otto Javascript interpreter. <https://github.com/robertkrimen/otto>

It provides some helper functions to
- load code from files
- run code snippets
- require libraries
- bind native go objects

Because of JSRE, an user can utilize JavaScript in the console as needed. JSRE also provides two JavaScript libraries, bignumber.js and web3.js, for users to easily access Klaytn.

Source Files

Each file provides following features

• completion.go : Provides functions for keyword completion
• jsre.go : Wraps otto JavaScript interpreter and provides an event loop
• pretty.go : Prints results to the standard output in more readable way

Index

• Variables
• func MakeCallback(vm *goja.Runtime, fn func(Call) (goja.Value, error)) goja.Value
• func SafeGet(obj *goja.Object, key string) (ret goja.Value)
• type Call
• type JSRE
  • func New(assetPath string, output io.Writer) *JSRE
  • func (re *JSRE) Compile(filename string, src string) (err error)
  • func (jsre *JSRE) CompleteKeywords(line string) []string
  • func (re *JSRE) Do(fn func(*goja.Runtime))
  • func (re *JSRE) Evaluate(code string, w io.Writer)
  • func (re *JSRE) Exec(file string) error
  • func (re *JSRE) Run(code string) (v goja.Value, err error)
  • func (re *JSRE) Set(ns string, v interface{}) (err error)
  • func (re *JSRE) Stop(waitForCallbacks bool)

Variables

var (
	FunctionColor = color.New(color.FgMagenta).SprintfFunc()
	SpecialColor  = color.New(color.Bold).SprintfFunc()
	NumberColor   = color.New(color.FgRed).SprintfFunc()
	StringColor   = color.New(color.FgGreen).SprintfFunc()
	ErrorColor    = color.New(color.FgHiRed).SprintfFunc()
)

Functions

func MakeCallback

func MakeCallback(vm *goja.Runtime, fn func(Call) (goja.Value, error)) goja.Value

MakeCallback turns the given function into a function that's callable by JS.

func SafeGet

func SafeGet(obj *goja.Object, key string) (ret goja.Value)

SafeGet attempt to get the value associated to `key`, and catches the panic that goja creates if an error occurs in key.

Types

type Call

type Call struct {
	goja.FunctionCall
	VM *goja.Runtime
}

Call is the argument type of Go functions which are callable from JS.

type JSRE

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

JSRE is a JS runtime environment embedding the goja interpreter. It provides helper functions to load code from files, run code snippets and bind native go objects to JS.

The runtime runs all code on a dedicated event loop and does not expose the underlying goja runtime directly. To use the runtime, call JSRE.Do. When binding a Go function, use the Call type to gain access to the runtime.

func New

func New(assetPath string, output io.Writer) *JSRE

runtime must be stopped with Stop() after use and cannot be used after stopping

func (*JSRE) Compile

func (re *JSRE) Compile(filename string, src string) (err error)

Compile compiles and then runs a piece of JS code.

func (*JSRE) CompleteKeywords

func (jsre *JSRE) CompleteKeywords(line string) []string

CompleteKeywords returns potential continuations for the given line. Since line is evaluated, callers need to make sure that evaluating line does not have side effects.

func (*JSRE) Do

func (re *JSRE) Do(fn func(*goja.Runtime))

Do executes the given function on the JS event loop.

func (*JSRE) Evaluate

func (re *JSRE) Evaluate(code string, w io.Writer)

Evaluate executes code and pretty prints the result to the specified output stream.

func (*JSRE) Exec

func (re *JSRE) Exec(file string) error

Exec(file) loads and runs the contents of a file if a relative path is given, the jsre's assetPath is used

func (*JSRE) Run

func (re *JSRE) Run(code string) (v goja.Value, err error)

Run runs a piece of JS code.

func (*JSRE) Set

func (re *JSRE) Set(ns string, v interface{}) (err error)

Set assigns value v to a variable in the JS environment.

func (*JSRE) Stop

func (re *JSRE) Stop(waitForCallbacks bool)

stops the event loop before exit, optionally waits for all timers to expire