Introduce ValueError and use it for panic messages (#16)

hajimehoshi · web-flow · commit 0765e455aaf6 · 2018-07-15T21:33:10.000+09:00
diff --git a/js/js_notwasm.go b/js/js_notwasm.go
@@ -189,6 +189,9 @@ func ValueOf(x interface{}) Value {
 }
 
 func (v Value) Bool() bool {
+	if vType := v.Type(); vType != TypeBoolean {
+		panic(&ValueError{"Value.Bool", vType})
+	}
 	return v.v.Bool()
 }
 
@@ -202,10 +205,19 @@ func convertArgs(args []interface{}) []interface{} {
 }
 
 func (v Value) Call(m string, args ...interface{}) Value {
+	if vType := v.Type(); vType != TypeObject && vType != TypeFunction {
+		panic(&ValueError{"Value.Call", vType})
+	}
+	if propType := v.Get(m).Type(); propType != TypeFunction {
+		panic("js: Value.Call: property " + m + " is not a function, got " + propType.String())
+	}
 	return Value{v: v.v.Call(m, convertArgs(args)...)}
 }
 
 func (v Value) Float() float64 {
+	if vType := v.Type(); vType != TypeNumber {
+		panic(&ValueError{"Value.Float", vType})
+	}
 	return v.v.Float()
 }
 
@@ -218,10 +230,16 @@ func (v Value) Index(i int) Value {
 }
 
 func (v Value) Int() int {
+	if vType := v.Type(); vType != TypeNumber {
+		panic(&ValueError{"Value.Int", vType})
+	}
 	return v.v.Int()
 }
 
 func (v Value) Invoke(args ...interface{}) Value {
+	if vType := v.Type(); vType != TypeFunction {
+		panic(&ValueError{"Value.Invoke", vType})
+	}
 	return Value{v: v.v.Invoke(convertArgs(args)...)}
 }
 
@@ -273,3 +291,12 @@ func (t *TypedArray) Release() {
 func GetInternalObject(v Value) interface{} {
 	return v.v
 }
+
+type ValueError struct {
+	Method string
+	Type   Type
+}
+
+func (e *ValueError) Error() string {
+	return "syscall/js: call of " + e.Method + " on " + e.Type.String()
+}
diff --git a/js/js_test.go b/js/js_test.go
@@ -54,6 +54,12 @@ func TestString(t *testing.T) {
 	if want := "Hello"; got != want {
 		t.Errorf("got %#v, want %#v", got, want)
 	}
+
+	obj = js.Global().Call("eval", "123")
+	got = obj.String()
+	if want := "123"; got != want {
+		t.Errorf("got %#v, want %#v", got, want)
+	}
 }
 
 func TestInt64(t *testing.T) {

Original file line number	Diff line number	Diff line change
`@@ -189,6 +189,9 @@ func ValueOf(x interface{}) Value {`
`189`	`189`	`}`
`190`	`190`
`191`	`191`	`func (v Value) Bool() bool {`
	`192`	`+ if vType := v.Type(); vType != TypeBoolean {`
	`193`	`+ panic(&ValueError{"Value.Bool", vType})`
	`194`	`+ }`
`192`	`195`	`return v.v.Bool()`
`193`	`196`	`}`
`194`	`197`
`@@ -202,10 +205,19 @@ func convertArgs(args []interface{}) []interface{} {`
`202`	`205`	`}`
`203`	`206`
`204`	`207`	`func (v Value) Call(m string, args ...interface{}) Value {`
	`208`	`+ if vType := v.Type(); vType != TypeObject && vType != TypeFunction {`
	`209`	`+ panic(&ValueError{"Value.Call", vType})`
	`210`	`+ }`
	`211`	`+ if propType := v.Get(m).Type(); propType != TypeFunction {`
	`212`	`+ panic("js: Value.Call: property " + m + " is not a function, got " + propType.String())`
	`213`	`+ }`
`205`	`214`	`return Value{v: v.v.Call(m, convertArgs(args)...)}`
`206`	`215`	`}`
`207`	`216`
`208`	`217`	`func (v Value) Float() float64 {`
	`218`	`+ if vType := v.Type(); vType != TypeNumber {`
	`219`	`+ panic(&ValueError{"Value.Float", vType})`
	`220`	`+ }`
`209`	`221`	`return v.v.Float()`
`210`	`222`	`}`
`211`	`223`
`@@ -218,10 +230,16 @@ func (v Value) Index(i int) Value {`
`218`	`230`	`}`
`219`	`231`
`220`	`232`	`func (v Value) Int() int {`
	`233`	`+ if vType := v.Type(); vType != TypeNumber {`
	`234`	`+ panic(&ValueError{"Value.Int", vType})`
	`235`	`+ }`
`221`	`236`	`return v.v.Int()`
`222`	`237`	`}`
`223`	`238`
`224`	`239`	`func (v Value) Invoke(args ...interface{}) Value {`
	`240`	`+ if vType := v.Type(); vType != TypeFunction {`
	`241`	`+ panic(&ValueError{"Value.Invoke", vType})`
	`242`	`+ }`
`225`	`243`	`return Value{v: v.v.Invoke(convertArgs(args)...)}`
`226`	`244`	`}`
`227`	`245`
`@@ -273,3 +291,12 @@ func (t *TypedArray) Release() {`
`273`	`291`	`func GetInternalObject(v Value) interface{} {`
`274`	`292`	`return v.v`
`275`	`293`	`}`
	`294`	`+`
	`295`	`+type ValueError struct {`
	`296`	`+ Method string`
	`297`	`+ Type Type`
	`298`	`+}`
	`299`	`+`
	`300`	`+func (e *ValueError) Error() string {`
	`301`	`+ return "syscall/js: call of " + e.Method + " on " + e.Type.String()`
	`302`	`+}`
Original file line number	Diff line number	Diff line change
`@@ -54,6 +54,12 @@ func TestString(t *testing.T) {`
`54`	`54`	`if want := "Hello"; got != want {`
`55`	`55`	`t.Errorf("got %#v, want %#v", got, want)`
`56`	`56`	`}`
	`57`	`+`
	`58`	`+ obj = js.Global().Call("eval", "123")`
	`59`	`+ got = obj.String()`
	`60`	`+ if want := "123"; got != want {`
	`61`	`+ t.Errorf("got %#v, want %#v", got, want)`
	`62`	`+ }`
`57`	`63`	`}`
`58`	`64`
`59`	`65`	`func TestInt64(t *testing.T) {`