在Golang中解组顶级json对象

I'm trying to parse a node package.json file in golang and I've got the following struct:

type packageJson struct {
    scripts         map[string]interface{} `json:"scripts"`
    dependencies    map[string]interface{} `json:"dependencies"`
    devDependencies map[string]interface{} `json:"devDependencies"`
}

...

var content packageJson
if err := json.Unmarshal(b, &content); err != nil {
    return err
}

When I parse the package file however the struct is not being populated (not getting an error though). I suspect it is because the content is an object itself (i.e.: { "scripts":"...", ... }) and the Unmarshal method wants to convert it into a map[string]interface{}. Any suggestions how to get around this "issue"? I tried creating a wrapper struct and using jpath but to no avail. Thanks!

Note: I could do this

var content map[string]interface{}
...
if val, ok := content["scripts"]; !ok { ... }

but I'd like to avoid it if possible.

You should make struct fields public.