Automatic Resolver Filtering with Wrappers

A common pattern is to filter information on Field Resolvers based on arguments from a query. In the case this pattern can be applied to multiple Field Resolvers it's useful to standardize this filtering with Resolver Wrappers. This helps separate filtering from the data resolution and allows for re-use. The nature of the filtering depends on the conventions of your GraphQL API.

Example

This Resolver Wrapper is an example of automatically filtering a list based on the arguments passed in. If a given key is provided it will filter any list down based on the value of the argument.

[object Promise]```

For this example the Query.movies resolver has the following data:

[object Promise]```

Then setting up the handler to apply the automaticFilter Wrapper against the Query.movies field resolver. The highlight argument can be customized to specify a specific selection of fields that should receive the automatic filter wrapper. Also, because there can be multiple Resolver Wrappers passed into the wrappers array, you could crete and combine multiple automatic filtering Field Wrappers to flexibly compose filtering across your fields.

The final query in the example, FilteredMovies, will automatically filter based on the query args { "year": "2001" } since year is an argument that also exists on the Movie type being filtered.

[object Promise]```

Result:

{
  "data": {
    "movies": [
      {
        "title": "Spirited Away",
        "year": "2001"
      },
      {
        "title": "Shrek",
        "year": "2001"
      }
    ]
  }
}

In the result the movie "La La Land" was filtered out since it was released in 2016 and the query specified movies with the year '2001'.

Example​

Example