How to get a specific translation of drupal node with graphql - drupal

Question

I am using drupal 8 to build a headless page with gatsby and graphql.
How to query a translation of a page?
query MyQuery {
allNodePage {
nodes {
body {
value
}
}
}
}
I want to get this allNodePage.nodes.body.value in a specific language.
Edit:
Here is the the graphiql allNodePage entity.
Edit_1:
According to this issue you can only query translations by modifying the api host-route (/fr/jsonapi/node/page) in drupal 8.
But in gatsby-source-drupal-plugin the api host route is not changeable in runtime.
Edit_2:
I try to translate a page node. Default language is english. I want to request the german translation which exists in drupal.

Answer 1

After some experimentation I see it's not working yet with Drupal JSON API, but I got it working with the Drupal GraphQL module. This can be used with Gatsby and gatsby-source-graphql instead of gatsby-source-drupal. The query would look something like this:
{
nodeQuery(
filter: {
conditions:[
{operator: IN, field: "type", value: ["my_node_type"]},
{operator: EQUAL, field: "langcode", value: "de"},
]
}
) {
entities {
...on NodeMyNodeType {
entityTranslation(language: DE) {
entityLabel
}
}
}
}
}

Answer 2

If you want to filter allNodePage by langcode you can do it like this:
query MyQuery {
allNodePage(filter: {langcode: {eq: "fr_FR"}}) {
nodes {
body {
value
}
}
}
}
Of course, you can use a variable in place of "fr_FR" instead of hardcoding it
query MyQuery($lang: String!) {
allNodePage(filter: {link: {eq: $lang:}}) {
nodes {
body {
value
}
}
}
}