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Query Building

groqd uses a builder pattern for building queries. Builder instances are created with a function q, and are chainable. There are four internal classes that are used as part of the query builder process: UnknownQuery, ArrayQuery, UnknownArrayQuery, and EntityQuery. These four classes have some overlap, but generally only contain methods that "make sense" for the type of result they represent (e.g. ArrayQuery will contain methods that an EntityQuery will not, such as ordering).

The q method​

The entry point for the query builder, which takes a base query as its sole argument (such as "*"). Returns an UnknownResult instance to be built upon.

const { query, schema } = q("*").filter("_type == 'pokemon'");

This function is best used in conjunction with a "query runner" from makeSafeQueryRunner, such as:

import sanityClient from "@sanity/client";
import { q, makeSafeQueryRunner } from "groqd";

// Wrap sanityClient.fetch
const client = sanityClient({
  /* ... */
});
export const runQuery = makeSafeQueryRunner((query) => client.fetch(query));

// Now you can fetch your query's result, and validate the response, all in one.
const data = await runQuery(q("*").filter("_type == 'pokemon'"));

Starting with an array​

Sometimes your base query returns an array. groqd has no way of knowing when this occurs, so you'll need to give it a hint by passing isArray: true to the second arg of q.

q("*[_type == 'pokemon']", { isArray: true })
  .grab$({ name: q.string() })

.filter​

Receives a single string argument for the GROQ filter to be applied (without the surrounding [ and ]). Applies the GROQ filter to the query and adjusts schema accordingly.

q("*").filter("_type == 'pokemon'");
// translates to: *[_type == 'pokemon']

.filterByType​

Receives a single string argument as a convenience method to apply a GROQ filter by type. Applies a GROQ filter by type to the query and adjusts schema accordingly.

q("*").filterByType("pokemon");
// translates to: *[_type == 'pokemon']

.grab​

Available on UnknownQuery, ArrayQuery, and EntityQuery, handles projections, or selecting fields from an existing set of documents. This is the primary mechanism for providing a schema for the data you expect to get.

q.grab accepts a "selection" object as its sole argument, with three different forms:

q("*").grab({
  // projection is `{ "name": name }`, and validates that `name` is a string.
  name: ["name", q.string()],

  // shorthand for `description: ['description', q.string()]`,
  //  projection is just `{ description }`
  description: q.string(),

  // can also pass a sub-query for the field,
  //  projection is `{ "types": types[]->{ name } }`
  types: q("types").filter().deref().grab({ name: q.string() }),
});

See Schema Types for available schema options, such as q.string(). These generally correspond to Zod primitives, so you can do something like:

q("*").grab({
  name: q.string().optional().default("no name"),
});

Conditional selections with .grab​

Grab accepts a second "Conditions" argument that comes in the shape { [condition: string]: Selection } . You can use this to create a union of possible selections that are merged with the base selection.

const pokemonQuery = q(*).filterByType('pokemon').grab(
  // Base selection
  {
    _key: q.string(),
    name: q.string()
  },
  // Conditional selections
  {
    'base.Attack > 60': {
      attack: 'strong',
      hp: ['base.HP', q.number()] 
    },
    'base.Attack <= 60': {
      attack: 'weak',
      defense: ['base.Defense', q.number()] 
    }
  }
)

type SanityPokemon = InferType<typeof pokemonQuery>
//    ^? (
//         | { _key: string; name: string; }
//         | { _key: string; name: string; attack: 'strong'; hp: number}
//         | { _key: string; name: string; attack: 'weak'; defense: number}
//       )[]

If you find that you are using the conditional argument with an empty base selection, we recommend using the .select method instead.

.grab$​

Just like .grab, but uses the nullToUndefined helper outlined here to convert null values to undefined which makes writing queries with "optional" values a bit easier.

q("*")
  .filter("_type == 'pokemon'")
  .grab$({
    name: q.string(),
    // 👇 `foo` comes in as `null`, but gets preprocessed to `undefined` so we can use `.optional()`.
    foo: q.string().optional().default("bar"),
  })

.grabOne​

Similar to q.grab, but for "naked" projections where you just need a single property (instead of an object of properties). Pass a property to be "grabbed", and a schema for the expected type.

q("*").filter("_type == 'pokemon'").grabOne("name", q.string());
// -> string[]

.grabOne$​

Just like .grabOne, but uses the nullToUndefined helper outlined below to convert null values to undefined which makes writing queries with "optional" values a bit easier.

q("*")
  .filter("_type == 'pokemon'")
  .grabOne$("name", q.string().optional());

.select​

GROQ offers a select operator that you can use at the field-level to conditionally select values, such as the following.

*{
  "strength": select(
    base.Attack > 60 => 'strong',
    base.Attack <= 60 => 'weak'
  )
}

Groqd provides a .select method to mirror this operator. This method provides field-level access exposed directly through q, while also providing entity level access exposed through the EntityQuery & ArrayQuery classes. The above query would be implemented like so.

q('*').grab({
  strength: q.select({
    'base.Attack > 60': ['"strong"', q.literal('strong')],
    'base.Attack <= 60': ['"weak"', q.literal('weak')]
  })
})

Args​

q.select accepts a "Conditions" object as its sole argument, with conditions in one of three different forms:

q('*').select({
  // Takes a raw [queryString, zodType] tuple. Creates the query string `base.Attack > 60 => name`
  'base.Attack > 60': ['name', q.string()]

  // Takes the "Selection" object used in `.grab` to create a projection. Creates the query string `base.Attack <= 60 => { name }`
  'base.Attack < 60': { name: q.string() }

  // Takes a sub-query for the condition. Creates the query string `base.Attack == 60 => types[]->{ name }`
  'base.Attack == 60': q("types").filter().deref().grab({ name: q.string() })
})

Similar to Groq's select operator, the q.select method also takes a default condition. If omitted, the condition { default: ['null', q.null()] } will be appended to the supplied conditions.

note

If used on an EntityQuery or ArrayQuery the select operator is spread into an entity context and will convert any primitives into an empty object (including the { default: null } condition if the default condition is omitted). This is why you often see empty objects show up in union types resulting from conditional selections.

"Fork" a selection based on a _type​

While some may find the flexibilty of .select useful, the most common Sanity use-cases center around modeling schema with an array of varying types. .select allows you to "fork" your selection (only one of the conditional selections will be made at any give time) and create a union of possible results. Here's an example.

q("*").filter().select({
  // For Bulbasaur, grab the HP
  'name == "Bulbasaur"': {
    _id: q.string(),
    name: q.literal("Bulbasaur"),
    hp: ["base.HP", q.number()],
  },
  // For Charmander, grab the Attack
  'name == "Charmander"': {
    _id: q.string(),
    name: q.literal("Charmander"),
    attack: ["base.Attack", q.number()],
  },
  // For all other pokemon, cast them into an unsupported selection
  // while retaining useful information for run-time logging
  default: {
    _id: q.string(),
    name: ['"unsupported pokemon"', q.literal("unsupported pokemon")],
    unsupportedName: ['name', q.string()]
  }
});

// The query result type looks like this:
type QueryResult = (
  | { _id: string; name: "Bulbasaur"; hp: number }
  | { _id: string; name: "Charmander"; attack: number }
  | { _id: string; name: "unsupported pokemon"; unsupportedName: string }
)[];
note

It is best practice to only provide conditions for supported types and cast the default condition as an unsupported selection. Making the default condition one of your supported return types can often introduce brittleness in your run-time validation.

This practice becomes evident when you add a new "fork" to content you have previously written a select query for. In that scenario, the ideal behavior is that the application does not fail run-time validation, and simply logs the unsupported type.

Composing large queries​

It is often the case that we want to break up our queries into more atomic pieces and compose them in larger queries later on (similar to the way we compose Sanity schema with components and documents). With this in mind, ArrayQuery.select & EntityQuery.select can accept a field level q.select in place of a "Conditions" argument.

This is useful when you have a Sanity component that consists of several "forked" types, that you later re-use in document level fields.

Lets take the previous pokemon example above and apply this technique to it.

// @/components/pokemon.tsx
import { q, type InferType } from 'groqd';

export const pokemonSelect = q.select({
  'name == "Bulbasaur"': {
    _id: q.string(),
    name: q.literal("Bulbasaur"),
    hp: ["base.HP", q.number()],
  },

  'name == "Charmander"': {
    _id: q.string(),
    name: q.literal("Charmander"),
    attack: ["base.Attack", q.number()],
  },

  default: {
    _id: q.string(),
    name: ['"unsupported pokemon"', q.literal("unsupported pokemon")],
    unsupportedName: ['name', q.string()]
  }
});

export default function Pokemon({ pokemon }: { pokemon: InferType<typeof pokemonSelect> }) {
  switch (pokemon.name) {
    case 'Bulbasaur': 
      return <Bulbasaur {...pokemon} />;

    case 'Charmander': 
      return <Charmander {...pokemon} />;

    case 'unsupported pokemon': 
    default:
      console.error(`unsupported pokemon type ${pokemon.unsupportedName}`)
      return null;
  }
}

// @/components/pokedex.tsx
import { pokemonSelect } from '@/components/pokemon'

const pokedexQuery = q('*').filterByType('Pokedex').grab({
  _key: q.string(),

  owner: q('owner')
    .deref()
    .grabOne('name', q.string()),

  pokemon: q('pokemon')
    .filter()
    .deref()
    .select(pokemonSelect)
})
/**
 * Resulting query string is:
 * ```groq
   *[_type == 'Pokedex']{
    _key,
    owner->name,
    pokemon[]->{
      ...select(
        name == "Bulbasaur" => {
          _id,
          name,
          "hp": base.HP
        },
        name == "Charmander" => {
          _id,
          name,
          "attack": base.Attack
        },
        {
          _id,
          "name": "unsupported pokemon",
          "unsupportedName": name
        }
      )
    }
   }
 * ```
 */
note

Types will differ slightly between q.select and (ArrayQuery | EntityQuery).select. With (ArrayQuery | EntityQuery).select possible selections are spread into the entity context entity{ ...select() }, so if any primitives are returned from an entity level select, they will be transformed into an empty object when spread.

If you run into this type mismatch when mapping component prop types to broader query types, it's recommended to encompass the select in an entity query when deriving the type to account for it being spread in larger queries

type someProperty = InferType<typeof q("").select(somePropertySelect)>

.slice​

Creates a slice operation by taking a minimum index and an optional maximum index.

q("*").filter("_type == 'pokemon'").grab({ name: q.string() }).slice(0, 8);
// translates to *[_type == 'pokemon']{name}[0..8]
// -> { name: string }[]
note

Groq slices are "closed" intervals, so the maximum index is included in the result. This can be a bit confusing when coming from JS Array.slice, since q("*").slice(0, 8) includes nine items – not eight.

.order​

Receives a list of ordering expression, such as "name asc", and adds an order statement to the GROQ query.

q("*").filter("_type == 'pokemon'").order("name asc");
// translates to *[_type == 'pokemon']|order(name asc)

.deref​

Used to apply the de-referencing operator ->.

q("*")
  .filter("_type == 'pokemon'")
  .grab({
    name: q.string(),
    // example of grabbing types for a pokemon, and de-referencing to get name value.
    types: q("types").filter().deref().grabOne("name", q.string()),
  });

.score​

Used to pipe a list of results through the score GROQ function.

// Fetch first 9 Pokemon's names, bubble Char* (Charmander, etc) to the top.
q("*")
  .filter("_type == 'pokemon'")
  .slice(0, 8)
  .score(`name match "char*"`)
  .order("_score desc")
  .grabOne("name", z.string());

.nullable​

A method on the base query class that allows you to mark a query's schema as nullable – in case you are expecting a potential null value.

q("*")
  .filter("_type == 'digimon'")
  .slice(0)
  .grab({ name: q.string() })
  .nullable(); // 👈 we're okay with a null value here