The push method cannot be called on the goarray object and errors will be reported

[hunjixin]

set a method that return a slice as result to vm, but if i call push method in js ,it will report a type error,
how can i resolve it ?

package main

import (
	"fmt"
	"github.com/robertkrimen/otto"
)
var (
	vm = otto.New()
)

func main(){
	vm.Set("returnarray", returnarray)

	_, err := vm.Run(`
	var arr = returnarray();
	arr.push("test")
`)
	if err != nil {
		fmt.Println(err.Error())
	}
}

func returnarray() otto.Value {
	arrValue,_ :=  vm.ToValue([]string{})
	return arrValue
}

[chrislowth]

I've had similar challenges with GO arrays converted to JS ones. You need to convert the array to a "TRUE" JS array before "push" and other calls can be made against it. One approach is to "clone" it. This works...

package main

import (
	"fmt"
	"github.com/robertkrimen/otto"
	_ "github.com/robertkrimen/otto/underscore" // ADDED
)
var (
	vm = otto.New()
)

func main(){
	vm.Set("returnarray", returnarray)

	_, err := vm.Run(`
	var arr = returnarray();
	arr = _.clone(arr) // ADDED
	arr.push("test")
`)
	if err != nil {
		fmt.Println(err.Error())
	}
}

func returnarray() otto.Value {
	arrValue,_ :=  vm.ToValue([]string{})
	return arrValue
}

[chrislowth]

I've done some more research and found the problem (though not solved it)...

A similar problem occurs when trying 'arr[0] = "test"' (though it fails silently) and seems to be because the "setValue" functions in type_go_array.go and type_go_slice.go test that the element already exists before allowing it to be set. This means that you cant change the length an array created in this way.

You can see this by replacing the "push" statement with...

arr[0] = "test"
console.log(arr.length)

Which shows 0 even though the element setting doesnt throw an error

[stevenh]

This should be fixed by #460