Relation

The field of type relation is used to create a relation to a document from a collection. It display a <select> in the UI.

Example

{
  name: "user",
  type: "relation",
  collection: "users",
  option: ({ label, flags }) => ({ label, value: flags.id })
}

Available options

In addition to the common options (see fields documentation for more info), this field has the following options:

collection

The collection name used to fetch the options.

option

A function to run per document that returns the label and value used in the interface.

Demo

Let's say we have a collection of countries with the following files:

/en-spain.json
/pt-portugal.json
/fr-france.json
/it-italy.json

We can configure the collection to extract the name and store the code as a flag:

cms.collection({
  name: "countries",
  documentLabel: (filename) => {
    const [code, name] = filename.replace(".json", "").split("-");
    return {
      label: name,
      flags: { code },
    };
  },
  // ...more options
});

Now we can use the relation field in other documents or collections:

cms.collection({
  name: "users",
  storage: "src:users/*.md",
  fields: [
    "name: text",
    {
      name: "country",
      type: "relation",
      collection: "countries",
      option: ({ label, flags }) => { label, value: flags.code }
    }
  ]
});

This field will show a selector to pick one of the countries and use the code flag as the value (en for Spain, pt for Portugal, etc).