Fix i18n support

[remidej]

What this does:

• Fix single types internationalization (fixes single type does not merge - can't query all locales #291)
• Introduce a new pluginOptions object in a content type's config object. Right now it's only to add an i18n key, but the goal is to be able to expand on it later, so that it eventually replaces queryParams altogether

First, I check if a content type has pluginOptions.i18n.locale defined. If it does, for collection types I set that value as the locale query param. For single types types, I do the same, except if the locale is "all", because it's not supported for single types in Strapi.

So in this case, I populate the localizations key in order to get the list of all available locales for a single type. Then, I make a dedicated request for each of these locales, so that they have the same response (level of population etc.) as the base request. I then merge all the localizations together with the default one.

How to test it:

• Create a Strapi app with the corporate template (because it has localized content)
• Create a Gatsby app with this config:

module.exports = {
  plugins: [
    {
      resolve: `gatsby-source-strapi`,
      options: {
        apiURL: "http://localhost:1337",
        accessToken: process.env.API_TOKEN,
        collectionTypes: [
          {
            singularName: 'page',
            pluginOptions: {
              i18n: {
                locale: 'fr' // try changing this
              }
            }
          }
        ],
        singleTypes: [
          {
            singularName: 'global',
            pluginOptions: {
              i18n: {
                locale: 'all', // try changing this
              },
            },
          }
        ],
      },
    },
  ],
}

• Open GraphiQL and query the different localizations of your content types

[markkaylor]

Nice work! Looks good to me

[markkaylor]

You can also provide an array of locales right? Don't know if it's worth mentioning

[remidej]

I don't think it's possible, it's either one locale or "all" to fetch everything

[markkaylor]

I tested with an array ["fr", "en"] and seemed to work but I'm not sure if it is defaulting to 'all' or fetching what is specified in the array.

[remidej]

I just checked and it seems to work indeed. But I see no mention of this in the Strapi i18n docs, so maybe we shouldn't document it either

[markkaylor]

agreed 👍