Clear context with nulls

[]

-

{
  "@context": {
    "@vocab": "http://example.com/vocab#",
    "ex": "http://example.com/ex#",
    "alias": { "@id": "ex:alias" },
    "ex:i18n": { "@container": "@language" }
  },
  "foo": 3,
  "ex:bar": 5,
  "alias": 8,
  "ex:i18n": "test",
  "ex:nested/one": {
    "@context": {
      "@vocab": null,
      "ex": null,
      "alias": null,
      "ex:i18n": null
    },
    "foo": 3,
    "ex:bar": 5,
    "alias": 8,
    "ex:i18n": "test"
  },
  "ex:nested/two": {
    "@context": null,
    "foo": 3,
    "ex:bar": 5,
    "alias": 8,
    "ex:i18n": "test"
  }
}

{
  "http://example.com/vocab#foo": 3,
  "http://example.com/ex#bar": 5,
  "http://example.com/ex#alias": 8,
  "http://example.com/ex#i18n": {
    "": "test"
  },
  "http://example.com/ex#nested/one": {
    "ex:bar": 5,
    "ex:i18n": "test"
  },
  "http://example.com/ex#nested/two": {
    "ex:bar": 5,
    "ex:i18n": "test"
  }
}