cmd, console: split off the console into a reusable package

internal/jsre/completion.go

@@ -0,0 +1,74 @@
+// Copyright 2016 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package jsre
+
+import (
+	"sort"
+	"strings"
+
+	"github.com/robertkrimen/otto"
+)
+
+// 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 *JSRE) CompleteKeywords(line string) []string {
+	var results []string
+	jsre.Do(func(vm *otto.Otto) {
+		results = getCompletions(vm, line)
+	})
+	return results
+}
+
+func getCompletions(vm *otto.Otto, line string) (results []string) {
+	parts := strings.Split(line, ".")
+	objRef := "this"
+	prefix := line
+	if len(parts) > 1 {
+		objRef = strings.Join(parts[0:len(parts)-1], ".")
+		prefix = parts[len(parts)-1]
+	}
+
+	obj, _ := vm.Object(objRef)
+	if obj == nil {
+		return nil
+	}
+	iterOwnAndConstructorKeys(vm, obj, func(k string) {
+		if strings.HasPrefix(k, prefix) {
+			if objRef == "this" {
+				results = append(results, k)
+			} else {
+				results = append(results, strings.Join(parts[:len(parts)-1], ".")+"."+k)
+			}
+		}
+	})
+
+	// Append opening parenthesis (for functions) or dot (for objects)
+	// if the line itself is the only completion.
+	if len(results) == 1 && results[0] == line {
+		obj, _ := vm.Object(line)
+		if obj != nil {
+			if obj.Class() == "Function" {
+				results[0] += "("
+			} else {
+				results[0] += "."
+			}
+		}
+	}
+
+	sort.Strings(results)
+	return results
+}

internal/jsre/completion_test.go

@@ -0,0 +1,88 @@
+// Copyright 2016 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package jsre
+
+import (
+	"os"
+	"reflect"
+	"testing"
+)
+
+func TestCompleteKeywords(t *testing.T) {
+	re := New("", os.Stdout)
+	re.Run(`
+		function theClass() {
+			this.foo = 3;
+			this.gazonk = {xyz: 4};
+		}
+		theClass.prototype.someMethod = function () {};
+  		var x = new theClass();
+  		var y = new theClass();
+		y.someMethod = function override() {};
+	`)
+
+	var tests = []struct {
+		input string
+		want  []string
+	}{
+		{
+			input: "x",
+			want:  []string{"x."},
+		},
+		{
+			input: "x.someMethod",
+			want:  []string{"x.someMethod("},
+		},
+		{
+			input: "x.",
+			want: []string{
+				"x.constructor",
+				"x.foo",
+				"x.gazonk",
+				"x.someMethod",
+			},
+		},
+		{
+			input: "y.",
+			want: []string{
+				"y.constructor",
+				"y.foo",
+				"y.gazonk",
+				"y.someMethod",
+			},
+		},
+		{
+			input: "x.gazonk.",
+			want: []string{
+				"x.gazonk.constructor",
+				"x.gazonk.hasOwnProperty",
+				"x.gazonk.isPrototypeOf",
+				"x.gazonk.propertyIsEnumerable",
+				"x.gazonk.toLocaleString",
+				"x.gazonk.toString",
+				"x.gazonk.valueOf",
+				"x.gazonk.xyz",
+			},
+		},
+	}
+	for _, test := range tests {
+		cs := re.CompleteKeywords(test.input)
+		if !reflect.DeepEqual(cs, test.want) {
+			t.Errorf("wrong completions for %q\ngot  %v\nwant %v", test.input, cs, test.want)
+		}
+	}
+}

internal/jsre/jsre.go

@@ -0,0 +1,327 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+// Package jsre provides execution environment for JavaScript.
+package jsre
+
+import (
+	crand "crypto/rand"
+	"encoding/binary"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"math/rand"
+	"sync"
+	"time"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/robertkrimen/otto"
+)
+
+/*
+JSRE is a generic JS runtime environment embedding the otto JS interpreter.
+It provides some helper functions to
+- load code from files
+- run code snippets
+- require libraries
+- bind native go objects
+*/
+type JSRE struct {
+	assetPath     string
+	output        io.Writer
+	evalQueue     chan *evalReq
+	stopEventLoop chan bool
+	loopWg        sync.WaitGroup
+}
+
+// jsTimer is a single timer instance with a callback function
+type jsTimer struct {
+	timer    *time.Timer
+	duration time.Duration
+	interval bool
+	call     otto.FunctionCall
+}
+
+// evalReq is a serialized vm execution request processed by runEventLoop.
+type evalReq struct {
+	fn   func(vm *otto.Otto)
+	done chan bool
+}
+
+// runtime must be stopped with Stop() after use and cannot be used after stopping
+func New(assetPath string, output io.Writer) *JSRE {
+	re := &JSRE{
+		assetPath:     assetPath,
+		output:        output,
+		evalQueue:     make(chan *evalReq),
+		stopEventLoop: make(chan bool),
+	}
+	re.loopWg.Add(1)
+	go re.runEventLoop()
+	re.Set("loadScript", re.loadScript)
+	re.Set("inspect", prettyPrintJS)
+	return re
+}
+
+// randomSource returns a pseudo random value generator.
+func randomSource() *rand.Rand {
+	bytes := make([]byte, 8)
+	seed := time.Now().UnixNano()
+	if _, err := crand.Read(bytes); err == nil {
+		seed = int64(binary.LittleEndian.Uint64(bytes))
+	}
+
+	src := rand.NewSource(seed)
+	return rand.New(src)
+}
+
+// This function runs the main event loop from a goroutine that is started
+// when JSRE is created. Use Stop() before exiting to properly stop it.
+// The event loop processes vm access requests from the evalQueue in a
+// serialized way and calls timer callback functions at the appropriate time.
+
+// Exported functions always access the vm through the event queue. You can
+// call the functions of the otto vm directly to circumvent the queue. These
+// functions should be used if and only if running a routine that was already
+// called from JS through an RPC call.
+func (self *JSRE) runEventLoop() {
+	vm := otto.New()
+	r := randomSource()
+	vm.SetRandomSource(r.Float64)
+
+	registry := map[*jsTimer]*jsTimer{}
+	ready := make(chan *jsTimer)
+
+	newTimer := func(call otto.FunctionCall, interval bool) (*jsTimer, otto.Value) {
+		delay, _ := call.Argument(1).ToInteger()
+		if 0 >= delay {
+			delay = 1
+		}
+		timer := &jsTimer{
+			duration: time.Duration(delay) * time.Millisecond,
+			call:     call,
+			interval: interval,
+		}
+		registry[timer] = timer
+
+		timer.timer = time.AfterFunc(timer.duration, func() {
+			ready <- timer
+		})
+
+		value, err := call.Otto.ToValue(timer)
+		if err != nil {
+			panic(err)
+		}
+		return timer, value
+	}
+
+	setTimeout := func(call otto.FunctionCall) otto.Value {
+		_, value := newTimer(call, false)
+		return value
+	}
+
+	setInterval := func(call otto.FunctionCall) otto.Value {
+		_, value := newTimer(call, true)
+		return value
+	}
+
+	clearTimeout := func(call otto.FunctionCall) otto.Value {
+		timer, _ := call.Argument(0).Export()
+		if timer, ok := timer.(*jsTimer); ok {
+			timer.timer.Stop()
+			delete(registry, timer)
+		}
+		return otto.UndefinedValue()
+	}
+	vm.Set("_setTimeout", setTimeout)
+	vm.Set("_setInterval", setInterval)
+	vm.Run(`var setTimeout = function(args) {
+		if (arguments.length < 1) {
+			throw TypeError("Failed to execute 'setTimeout': 1 argument required, but only 0 present.");
+		}
+		return _setTimeout.apply(this, arguments);
+	}`)
+	vm.Run(`var setInterval = function(args) {
+		if (arguments.length < 1) {
+			throw TypeError("Failed to execute 'setInterval': 1 argument required, but only 0 present.");
+		}
+		return _setInterval.apply(this, arguments);
+	}`)
+	vm.Set("clearTimeout", clearTimeout)
+	vm.Set("clearInterval", clearTimeout)
+
+	var waitForCallbacks bool
+
+loop:
+	for {
+		select {
+		case timer := <-ready:
+			// execute callback, remove/reschedule the timer
+			var arguments []interface{}
+			if len(timer.call.ArgumentList) > 2 {
+				tmp := timer.call.ArgumentList[2:]
+				arguments = make([]interface{}, 2+len(tmp))
+				for i, value := range tmp {
+					arguments[i+2] = value
+				}
+			} else {
+				arguments = make([]interface{}, 1)
+			}
+			arguments[0] = timer.call.ArgumentList[0]
+			_, err := vm.Call(`Function.call.call`, nil, arguments...)
+			if err != nil {
+				fmt.Println("js error:", err, arguments)
+			}
+
+			_, inreg := registry[timer] // when clearInterval is called from within the callback don't reset it
+			if timer.interval && inreg {
+				timer.timer.Reset(timer.duration)
+			} else {
+				delete(registry, timer)
+				if waitForCallbacks && (len(registry) == 0) {
+					break loop
+				}
+			}
+		case req := <-self.evalQueue:
+			// run the code, send the result back
+			req.fn(vm)
+			close(req.done)
+			if waitForCallbacks && (len(registry) == 0) {
+				break loop
+			}
+		case waitForCallbacks = <-self.stopEventLoop:
+			if !waitForCallbacks || (len(registry) == 0) {
+				break loop
+			}
+		}
+	}
+
+	for _, timer := range registry {
+		timer.timer.Stop()
+		delete(registry, timer)
+	}
+
+	self.loopWg.Done()
+}
+
+// Do executes the given function on the JS event loop.
+func (self *JSRE) Do(fn func(*otto.Otto)) {
+	done := make(chan bool)
+	req := &evalReq{fn, done}
+	self.evalQueue <- req
+	<-done
+}
+
+// stops the event loop before exit, optionally waits for all timers to expire
+func (self *JSRE) Stop(waitForCallbacks bool) {
+	self.stopEventLoop <- waitForCallbacks
+	self.loopWg.Wait()
+}
+
+// Exec(file) loads and runs the contents of a file
+// if a relative path is given, the jsre's assetPath is used
+func (self *JSRE) Exec(file string) error {
+	code, err := ioutil.ReadFile(common.AbsolutePath(self.assetPath, file))
+	if err != nil {
+		return err
+	}
+	var script *otto.Script
+	self.Do(func(vm *otto.Otto) {
+		script, err = vm.Compile(file, code)
+		if err != nil {
+			return
+		}
+		_, err = vm.Run(script)
+	})
+	return err
+}
+
+// Bind assigns value v to a variable in the JS environment
+// This method is deprecated, use Set.
+func (self *JSRE) Bind(name string, v interface{}) error {
+	return self.Set(name, v)
+}
+
+// Run runs a piece of JS code.
+func (self *JSRE) Run(code string) (v otto.Value, err error) {
+	self.Do(func(vm *otto.Otto) { v, err = vm.Run(code) })
+	return v, err
+}
+
+// Get returns the value of a variable in the JS environment.
+func (self *JSRE) Get(ns string) (v otto.Value, err error) {
+	self.Do(func(vm *otto.Otto) { v, err = vm.Get(ns) })
+	return v, err
+}
+
+// Set assigns value v to a variable in the JS environment.
+func (self *JSRE) Set(ns string, v interface{}) (err error) {
+	self.Do(func(vm *otto.Otto) { err = vm.Set(ns, v) })
+	return err
+}
+
+// loadScript executes a JS script from inside the currently executing JS code.
+func (self *JSRE) loadScript(call otto.FunctionCall) otto.Value {
+	file, err := call.Argument(0).ToString()
+	if err != nil {
+		// TODO: throw exception
+		return otto.FalseValue()
+	}
+	file = common.AbsolutePath(self.assetPath, file)
+	source, err := ioutil.ReadFile(file)
+	if err != nil {
+		// TODO: throw exception
+		return otto.FalseValue()
+	}
+	if _, err := compileAndRun(call.Otto, file, source); err != nil {
+		// TODO: throw exception
+		fmt.Println("err:", err)
+		return otto.FalseValue()
+	}
+	// TODO: return evaluation result
+	return otto.TrueValue()
+}
+
+// Evaluate executes code and pretty prints the result to the specified output
+// stream.
+func (self *JSRE) Evaluate(code string, w io.Writer) error {
+	var fail error
+
+	self.Do(func(vm *otto.Otto) {
+		val, err := vm.Run(code)
+		if err != nil {
+			fail = err
+		} else {
+			prettyPrint(vm, val, w)
+			fmt.Fprintln(w)
+		}
+	})
+	return fail
+}
+
+// Compile compiles and then runs a piece of JS code.
+func (self *JSRE) Compile(filename string, src interface{}) (err error) {
+	self.Do(func(vm *otto.Otto) { _, err = compileAndRun(vm, filename, src) })
+	return err
+}
+
+func compileAndRun(vm *otto.Otto, filename string, src interface{}) (otto.Value, error) {
+	script, err := vm.Compile(filename, src)
+	if err != nil {
+		return otto.Value{}, err
+	}
+	return vm.Run(script)
+}

internal/jsre/jsre_test.go

@@ -0,0 +1,137 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package jsre
+
+import (
+	"io/ioutil"
+	"os"
+	"path"
+	"testing"
+	"time"
+
+	"github.com/robertkrimen/otto"
+)
+
+type testNativeObjectBinding struct{}
+
+type msg struct {
+	Msg string
+}
+
+func (no *testNativeObjectBinding) TestMethod(call otto.FunctionCall) otto.Value {
+	m, err := call.Argument(0).ToString()
+	if err != nil {
+		return otto.UndefinedValue()
+	}
+	v, _ := call.Otto.ToValue(&msg{m})
+	return v
+}
+
+func newWithTestJS(t *testing.T, testjs string) (*JSRE, string) {
+	dir, err := ioutil.TempDir("", "jsre-test")
+	if err != nil {
+		t.Fatal("cannot create temporary directory:", err)
+	}
+	if testjs != "" {
+		if err := ioutil.WriteFile(path.Join(dir, "test.js"), []byte(testjs), os.ModePerm); err != nil {
+			t.Fatal("cannot create test.js:", err)
+		}
+	}
+	return New(dir, os.Stdout), dir
+}
+
+func TestExec(t *testing.T) {
+	jsre, dir := newWithTestJS(t, `msg = "testMsg"`)
+	defer os.RemoveAll(dir)
+
+	err := jsre.Exec("test.js")
+	if err != nil {
+		t.Errorf("expected no error, got %v", err)
+	}
+	val, err := jsre.Run("msg")
+	if err != nil {
+		t.Errorf("expected no error, got %v", err)
+	}
+	if !val.IsString() {
+		t.Errorf("expected string value, got %v", val)
+	}
+	exp := "testMsg"
+	got, _ := val.ToString()
+	if exp != got {
+		t.Errorf("expected '%v', got '%v'", exp, got)
+	}
+	jsre.Stop(false)
+}
+
+func TestNatto(t *testing.T) {
+	jsre, dir := newWithTestJS(t, `setTimeout(function(){msg = "testMsg"}, 1);`)
+	defer os.RemoveAll(dir)
+
+	err := jsre.Exec("test.js")
+	if err != nil {
+		t.Errorf("expected no error, got %v", err)
+	}
+	time.Sleep(100 * time.Millisecond)
+	val, err := jsre.Run("msg")
+	if err != nil {
+		t.Errorf("expected no error, got %v", err)
+	}
+	if !val.IsString() {
+		t.Errorf("expected string value, got %v", val)
+	}
+	exp := "testMsg"
+	got, _ := val.ToString()
+	if exp != got {
+		t.Errorf("expected '%v', got '%v'", exp, got)
+	}
+	jsre.Stop(false)
+}
+
+func TestBind(t *testing.T) {
+	jsre := New("", os.Stdout)
+	defer jsre.Stop(false)
+
+	jsre.Bind("no", &testNativeObjectBinding{})
+
+	_, err := jsre.Run(`no.TestMethod("testMsg")`)
+	if err != nil {
+		t.Errorf("expected no error, got %v", err)
+	}
+}
+
+func TestLoadScript(t *testing.T) {
+	jsre, dir := newWithTestJS(t, `msg = "testMsg"`)
+	defer os.RemoveAll(dir)
+
+	_, err := jsre.Run(`loadScript("test.js")`)
+	if err != nil {
+		t.Errorf("expected no error, got %v", err)
+	}
+	val, err := jsre.Run("msg")
+	if err != nil {
+		t.Errorf("expected no error, got %v", err)
+	}
+	if !val.IsString() {
+		t.Errorf("expected string value, got %v", val)
+	}
+	exp := "testMsg"
+	got, _ := val.ToString()
+	if exp != got {
+		t.Errorf("expected '%v', got '%v'", exp, got)
+	}
+	jsre.Stop(false)
+}

internal/jsre/pretty.go

@@ -0,0 +1,262 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package jsre
+
+import (
+	"fmt"
+	"io"
+	"sort"
+	"strconv"
+	"strings"
+
+	"github.com/fatih/color"
+	"github.com/robertkrimen/otto"
+)
+
+const (
+	maxPrettyPrintLevel = 3
+	indentString        = "  "
+)
+
+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()
+)
+
+// these fields are hidden when printing objects.
+var boringKeys = map[string]bool{
+	"valueOf":              true,
+	"toString":             true,
+	"toLocaleString":       true,
+	"hasOwnProperty":       true,
+	"isPrototypeOf":        true,
+	"propertyIsEnumerable": true,
+	"constructor":          true,
+}
+
+// prettyPrint writes value to standard output.
+func prettyPrint(vm *otto.Otto, value otto.Value, w io.Writer) {
+	ppctx{vm: vm, w: w}.printValue(value, 0, false)
+}
+
+func prettyPrintJS(call otto.FunctionCall, w io.Writer) otto.Value {
+	for _, v := range call.ArgumentList {
+		prettyPrint(call.Otto, v, w)
+		fmt.Fprintln(w)
+	}
+	return otto.UndefinedValue()
+}
+
+type ppctx struct {
+	vm *otto.Otto
+	w  io.Writer
+}
+
+func (ctx ppctx) indent(level int) string {
+	return strings.Repeat(indentString, level)
+}
+
+func (ctx ppctx) printValue(v otto.Value, level int, inArray bool) {
+	switch {
+	case v.IsObject():
+		ctx.printObject(v.Object(), level, inArray)
+	case v.IsNull():
+		fmt.Fprint(ctx.w, SpecialColor("null"))
+	case v.IsUndefined():
+		fmt.Fprint(ctx.w, SpecialColor("undefined"))
+	case v.IsString():
+		s, _ := v.ToString()
+		fmt.Fprint(ctx.w, StringColor("%q", s))
+	case v.IsBoolean():
+		b, _ := v.ToBoolean()
+		fmt.Fprint(ctx.w, SpecialColor("%t", b))
+	case v.IsNaN():
+		fmt.Fprint(ctx.w, NumberColor("NaN"))
+	case v.IsNumber():
+		s, _ := v.ToString()
+		fmt.Fprint(ctx.w, NumberColor("%s", s))
+	default:
+		fmt.Fprint(ctx.w, "<unprintable>")
+	}
+}
+
+func (ctx ppctx) printObject(obj *otto.Object, level int, inArray bool) {
+	switch obj.Class() {
+	case "Array":
+		lv, _ := obj.Get("length")
+		len, _ := lv.ToInteger()
+		if len == 0 {
+			fmt.Fprintf(ctx.w, "[]")
+			return
+		}
+		if level > maxPrettyPrintLevel {
+			fmt.Fprint(ctx.w, "[...]")
+			return
+		}
+		fmt.Fprint(ctx.w, "[")
+		for i := int64(0); i < len; i++ {
+			el, err := obj.Get(strconv.FormatInt(i, 10))
+			if err == nil {
+				ctx.printValue(el, level+1, true)
+			}
+			if i < len-1 {
+				fmt.Fprintf(ctx.w, ", ")
+			}
+		}
+		fmt.Fprint(ctx.w, "]")
+
+	case "Object":
+		// Print values from bignumber.js as regular numbers.
+		if ctx.isBigNumber(obj) {
+			fmt.Fprint(ctx.w, NumberColor("%s", toString(obj)))
+			return
+		}
+		// Otherwise, print all fields indented, but stop if we're too deep.
+		keys := ctx.fields(obj)
+		if len(keys) == 0 {
+			fmt.Fprint(ctx.w, "{}")
+			return
+		}
+		if level > maxPrettyPrintLevel {
+			fmt.Fprint(ctx.w, "{...}")
+			return
+		}
+		fmt.Fprintln(ctx.w, "{")
+		for i, k := range keys {
+			v, _ := obj.Get(k)
+			fmt.Fprintf(ctx.w, "%s%s: ", ctx.indent(level+1), k)
+			ctx.printValue(v, level+1, false)
+			if i < len(keys)-1 {
+				fmt.Fprintf(ctx.w, ",")
+			}
+			fmt.Fprintln(ctx.w)
+		}
+		if inArray {
+			level--
+		}
+		fmt.Fprintf(ctx.w, "%s}", ctx.indent(level))
+
+	case "Function":
+		// Use toString() to display the argument list if possible.
+		if robj, err := obj.Call("toString"); err != nil {
+			fmt.Fprint(ctx.w, FunctionColor("function()"))
+		} else {
+			desc := strings.Trim(strings.Split(robj.String(), "{")[0], " \t\n")
+			desc = strings.Replace(desc, " (", "(", 1)
+			fmt.Fprint(ctx.w, FunctionColor("%s", desc))
+		}
+
+	case "RegExp":
+		fmt.Fprint(ctx.w, StringColor("%s", toString(obj)))
+
+	default:
+		if v, _ := obj.Get("toString"); v.IsFunction() && level <= maxPrettyPrintLevel {
+			s, _ := obj.Call("toString")
+			fmt.Fprintf(ctx.w, "<%s %s>", obj.Class(), s.String())
+		} else {
+			fmt.Fprintf(ctx.w, "<%s>", obj.Class())
+		}
+	}
+}
+
+func (ctx ppctx) fields(obj *otto.Object) []string {
+	var (
+		vals, methods []string
+		seen          = make(map[string]bool)
+	)
+	add := func(k string) {
+		if seen[k] || boringKeys[k] || strings.HasPrefix(k, "_") {
+			return
+		}
+		seen[k] = true
+		if v, _ := obj.Get(k); v.IsFunction() {
+			methods = append(methods, k)
+		} else {
+			vals = append(vals, k)
+		}
+	}
+	iterOwnAndConstructorKeys(ctx.vm, obj, add)
+	sort.Strings(vals)
+	sort.Strings(methods)
+	return append(vals, methods...)
+}
+
+func iterOwnAndConstructorKeys(vm *otto.Otto, obj *otto.Object, f func(string)) {
+	seen := make(map[string]bool)
+	iterOwnKeys(vm, obj, func(prop string) {
+		seen[prop] = true
+		f(prop)
+	})
+	if cp := constructorPrototype(obj); cp != nil {
+		iterOwnKeys(vm, cp, func(prop string) {
+			if !seen[prop] {
+				f(prop)
+			}
+		})
+	}
+}
+
+func iterOwnKeys(vm *otto.Otto, obj *otto.Object, f func(string)) {
+	Object, _ := vm.Object("Object")
+	rv, _ := Object.Call("getOwnPropertyNames", obj.Value())
+	gv, _ := rv.Export()
+	switch gv := gv.(type) {
+	case []interface{}:
+		for _, v := range gv {
+			f(v.(string))
+		}
+	case []string:
+		for _, v := range gv {
+			f(v)
+		}
+	default:
+		panic(fmt.Errorf("Object.getOwnPropertyNames returned unexpected type %T", gv))
+	}
+}
+
+func (ctx ppctx) isBigNumber(v *otto.Object) bool {
+	// Handle numbers with custom constructor.
+	if v, _ := v.Get("constructor"); v.Object() != nil {
+		if strings.HasPrefix(toString(v.Object()), "function BigNumber") {
+			return true
+		}
+	}
+	// Handle default constructor.
+	BigNumber, _ := ctx.vm.Object("BigNumber.prototype")
+	if BigNumber == nil {
+		return false
+	}
+	bv, _ := BigNumber.Call("isPrototypeOf", v)
+	b, _ := bv.ToBoolean()
+	return b
+}
+
+func toString(obj *otto.Object) string {
+	s, _ := obj.Call("toString")
+	return s.String()
+}
+
+func constructorPrototype(obj *otto.Object) *otto.Object {
+	if v, _ := obj.Get("constructor"); v.Object() != nil {
+		if v, _ = v.Object().Get("prototype"); v.Object() != nil {
+			return v.Object()
+		}
+	}
+	return nil
+}