gql.tada API

Functions

graphql()

	Description
input argument	A string of a GraphQL document.
fragments argument	An optional list of other GraphQL fragments created with this function.
returns	A GraphQL DocumentNode with result and variables types.

Creates a DocumentNode with result and variables types.

You can compose fragments into this function by passing them and a fragment mask will be created for them. When creating queries, the returned document of queries can be passed into GraphQL clients which will then automatically infer the result and variables types.

It is used with your schema in setupSchema to create a result type of your queries, fragments, and variables. If you instead would like to manually create a graphql function with an explicit schema type, use initGraphQLTada instead.

Example

import { graphql } from 'gql.tada';
const bookFragment = graphql(`
  fragment BookComponent on Book {
    id
    title
  }
`);

const bookQuery = graphql(`
  query Book ($id: ID!) {
    book(id: $id) {
      id
      ...BookComponent
    }
  }
`, [bookFragment]);

graphql.scalar()

	Description
name argument	A name of a GraphQL scalar or enum.
value argument	The value to be type-checked against the type.
returns	The value will be returned directly.

Type checks a given input value to be of a scalar or enum type and returns the value directly.

You can use this utility to add a type check for a scalar or enum value, or to retrieve the type of a scalar or enum. This is useful if you’re writing a function or component that only accepts a scalar or enum, but not a full fragment.

Note

It’s not recommended to use this utiliy to replace fragments, i.e. to create your own object types. Try to use fragments where appropriate instead.

Example

import { graphql } from 'gql.tada';

function validateMediaEnum(value: 'Book' | 'Song' | 'Video') {

  const media = graphql.scalar('Media', value);
}


type Media = ReturnType<typeof graphql.scalar<'Media'>>;

readFragment()

	Description
_document argument	A GraphQL document of a fragment, created using graphql().
fragment argument	A mask of the fragment, which can be wrapped in arrays, or nullable.
returns	The unmasked data of the fragment.

When graphql() is used to create a fragment and is spread into another fragment or query, their result types will only contain a “reference” to the fragment. This encourages isolation and is known as “fragment masking.”

This means that you must use readFragment() to unmask these fragment masks and get to the data. This encourages isolation and only using the data you define a part of your codebase to require.

When passing fragment masks to readFragment(), you may also pass nullable, optional data, or data wrapped in arrays to readFragment() and the result type will be unwrapped and inferred accordingly.

Read more about fragment masking on the “Writing GraphQL” page.

Example

import { FragmentOf, graphql, readFragment } from 'gql.tada';

const bookFragment = graphql(`
  fragment BookComponent on Book {
    id
    title
  }
`);

const getBook = (data: FragmentOf<typeof bookFragment> | null) => {
  // Unmasks the fragment and casts to the result type of `bookFragment`
  // This is intersected with `| null` in this case, due to the input type.
  const book = readFragment(bookFragment, data);
};

const bookQuery = graphql(`
  query Book ($id: ID!) {
    book(id: $id) {
      id
      ...BookComponent
    }
  }
`, [bookFragment]);

const getQuery = (data: ResultOf<typeof bookQuery>) => {
  getBook(data?.book);
};

maskFragments()

	Description
_fragments argument	A list of GraphQL documents of fragments, created using graphql().
data argument	The combined result data of the fragments, which can be wrapped in arrays.
returns	The masked data of the fragments.

Note

While useful, maskFragments() is mostly meant to be used in tests or as an escape hatch to convert data to masked fragments.

You shouldn’t have to use it in your regular component code.

When graphql() is used to compose fragments into another fragment or operation, the resulting type will by default be masked, unless the @_unmask directive is used.

This means that when we’re writing tests or are creating “fake data” without inferring types from a full document, the types in TypeScript may not match, since our testing data will not be masked and will be equal to the result type of the fragments.

To address this, the maskFragments utility takes a list of fragments and masks data (or an array of data) to match the masked fragment types of the fragments.

• Read more about fragment masking on the “Writing GraphQL” page.
• For the reverse operation, see readFragment().

Example

import { graphql, maskFragments } from 'gql.tada';

const bookFragment = graphql(`
  fragment BookComponent on Book {
    id
    title
  }
`);

// `data` will be typed as the fragment mask of `bookFragment`.
const data = maskFragments([bookFragment], { id: 'id', title: 'book' });

unsafe_readResult()

	Description
_document argument	A GraphQL document, created using graphql().
data argument	The result data of the GraphQL document with optional fragment refs.
returns	The masked result data of the document.

Caution

Unlike, maskFragments(), this utility is unsafe, and should only be used when you know that data matches the expected shape of a GraphQL query you created.

While useful, this utility is only a slightly safer alternative to as any and doesn’t type check the result shape against the masked fragments in your document.

You shouldn’t have to use it in your regular app code.

When graphql() is used to compose fragments into a document, the resulting type will by default be masked, unless the @_unmask directive is used.

This means that when we’re writing tests and are creating “fake data”, for instance for a query, that we cannot convert this data to the query’s result type, if it contains masked fragment refs.

To address this, the unsafe_readResult utility accepts the document and converts a query’s data to masked data.

Example

import { graphql, unsafe_readResult } from 'gql.tada';

const bookFragment = graphql(`
  fragment BookComponent on Book {
    id
    title
  }
`);

const query = graphql(`
  query {
    book {
      ...BookComponent
    }
  }
`, [bookFragment]);

// `data` will be cast (unsafely!) to the result type of `query`.
const data = unsafe_readResult(query, { book: { id: 'id', title: 'book' } });

initGraphQLTada()

	Description
Setup generic	An AbstractSetupSchema configuration object
returns	A typed graphql() function.

initGraphQLTada accepts an AbstractSetupSchema configuration object as a generic and returns a graphql() function that may be used to create documents typed using your GraphQL schema.

You should use and re-export the resulting function named as graphql or gql for your editor and the TypeScript language server to recognize your GraphQL documents correctly.

Read more about how to use initGraphQLTada() on the “Installation” page.

Example

import { initGraphQLTada } from 'gql.tada';
import type { introspection } from './graphql-env.d.ts';

export const graphql = initGraphQLTada<{
  introspection: introspection;
  scalars: {
    DateTime: string;
    Json: any;
  };
}>();

const query = graphql(`{ __typename }`);

Types

ResultOf

	Description
Document generic	The document type of a DocumentNode carrying the result type.

This accepts a TadaDocumentNode and returns the attached Result type of GraphQL documents.

VariablesOf

	Description
Document generic	The document type of a DocumentNode carrying the variables type.

This accepts a TadaDocumentNode and returns the attached Variables type of GraphQL documents.

FragmentOf

	Description
Document generic	A DocumentNode containing a fragment definition.

Creates a fragment mask for a given fragment document.

When graphql() is used to create a fragment and is spread into another fragment or query, their result types will only contain a “reference” to the fragment. This encourages isolation and is known as “fragment masking.”

While readFragment() is used to unmask these fragment masks, this utility creates a fragment mask, so you can accept the masked data in the part of your codebase that defines a fragment.

Read more about fragment masking on the “Writing GraphQL” page.

Example

import { FragmentOf, graphql, readFragment } from 'gql.tada';
const bookFragment = graphql(`
  fragment BookComponent on Book {
    id
    title
  }
`);

// May be called with any GraphQL data that contains a spread of `bookFragment`
const getBook = (data: FragmentOf<typeof bookFragment>) => {
  // Unmasks the fragment and casts to the result type of `bookFragment`
  const book = readFragment(bookFragment, data);
};

TadaDocumentNode

	Description
Result generic	The type of GraphQL results, as returned by GraphQL APIs for a given query.
Variables generic	The type of variables, as accepted by GraphQL APIs for a given query.

A GraphQL DocumentNode with attached types for results and variables.

This is a GraphQL DocumentNode with attached types for results and variables. This is used by GraphQL clients to infer the types of results and variables and provide type-safety in GraphQL documents.

You can create typed GraphQL documents using the graphql() function.

setupSchema

You may extend this interface via declaration merging with your IntrospectionQuery data and optionally your scalars to get proper type inference. This is done by declaring a declaration for it as per the following example.

Configuring scalars is optional and by default the standard scalrs are already defined.

This will configure the default graphql() export to infer types from your schema. Alternatively, if you don’t want to define your schema project-wide, you may call initGraphQLTada() instead.

Read more about setting up your schema on the “Installation” page.

Example

import type { introspection } from './graphql-env.d.ts';

declare module 'gql.tada' {
  interface setupSchema {
    introspection: introspection;
    scalars: {
      DateTime: string;
      Json: any;
    };
  }
}

AbstractSetupSchema

	Description
introspection property	Introspection of your schema in the IntrospectionQuery format.
scalars property	An optional object type with scalar names as keys and the corresponding scalar types as values.

This is used either via setupSchema or initGraphQLTada() to set up your schema and scalars. Your configuration objects must match the shape of this type.

The scalars option is optional and can be used to set up more scalars, apart from the default ones (like: Int, Float, String, Boolean). It must be an object map of scalar names to their desired TypeScript types.