This project is inspired by Apollo-codegen. Currently apollo-codegen only generate TypeScripts for GraphQL Client. The shape of the generated type is based on the client's query strings.
This module aim to do the Server counterpart: from a Schema Definition, generate the types to make it type-safed when developing GraphQL server (mainly resolvers)
graphql-schema-typescript | graphql |
---|---|
1.6 | ^16.0.0 |
1.5 | ^14.0.0, ^15.0.0 |
1.4 | 0.11~0.13 |
VSCode extension (credit to @liyikun)
import { generateTypeScriptTypes } from 'graphql-schema-typescript';
generateTypeScriptTypes(schema, outputPath, options)
.then(() => {
console.log('DONE');
process.exit(0);
})
.catch(err =>{
console.error(err);
process.exit(1);
});
You can then bootstrap this script on your dev server, or use something like ts-node to execute it directly
schema
: your graphql schemaoutputPath
: where the types is generatedoptions
: see GenerateTypescriptOptions
- You can also use CLIs to generate your TypeScript instead of writing code
- Instead of providing a schema, you need to provide a folder that contains your type definitions, written in .gql or .graphql extensions
- Use
graphql-schema-typescript generate-ts --help
for more details
The file generated will have some types that can make it type-safed when writing resolver:
- Args type in your resolve function is now type-safed
- Parent type and resolve result is default to
any
, but could be overwritten in your code
For example, if you schema is like this:
schema {
query: RootQuery
}
type RootQuery {
Users(input: UserFilter): [User!]!
# ... some more fields here
}
input UserFilter {
username: [String]
}
type User {
firstName: String!
# ... some more fields here
}
Then the tools will generate TypeScripts like this:
/**
* This interface define the shape of your resolver
* Note that this type is designed to be compatible with graphql-tools resolvers
* However, you can still use other generated interfaces to make your resolver type-safed
*/
export interface GQLResolver {
RootQuery?: GQLRootQueryTypeResolver;
User?: GQLUserTypeResolver;
}
export interface GQLRootQueryTypeResolver {
Users?: RootQueryToUsersResolver;
}
export interface RootQueryToUsersArgs {
Users?: GQLUserFilter;
}
export interface RootQueryToUsersResolver<TParent = any, TResult = any> {
(parent: TParent, args: RootQueryToUsersArgs, context: any, info: GraphQLResolveInfo): TResult;
}
In this example, if you are not using graphql-tools,
you can still use RootQueryToUsersResolver
type to make your args type safed.
In version 1.2.2, a strategy for generating default TParent and TResult has been implemented
by setting smartTParent
and smartTResult
options to true.
If both options are set to true, the resolver will be generated as follow:
// smartTParent: true
// smartTResult: true
// TParent is undefined because it uses the value of 'rootValueType' in options
export interface RootQueryToUsersResolver<TParent = undefined, TResult = Array<GQLUser> {
(parent: TParent, args: RootQueryToUsersArgs, context: any, info: GraphQLResolveInfo): TResult;
}
However, since RootQueryToUsersResolver
usually will be asynchronous operation,
the default TResult would not be too helpful, as developers would most likely overwrite it to Promise<Array<GQLUser>>
. Therefore, another option , asyncResult
, was implemented. This option
basically allow resolver to return promises
// smartTParent: true
// smartTResult: true
// asyncResult: true
export interface RootQueryToUsersResolver<TParent = undefined, TResult = Array<GQLUser> {
(parent: TParent, args: RootQueryToUsersArgs, context: any, info: GraphQLResolveInfo): Promise<TResult> | TResult; // the different is here
}
// in v1.12.11, asyncResult also accept string value 'always',
// which will make returns value of resolve functions to be `Promise<TResult>`,
// due to an issue with VSCode that not showing auto completion when returns is a mix of `T | Promise<T>` (see [#17](https://github.com/dangcuuson/graphql-schema-typescript/issues/17))
// smartTParent: true
// smartTResult: true
// asyncResult: 'always'
export interface RootQueryToUsersResolver<TParent = undefined, TResult = Array<GQLUser> {
(parent: TParent, args: RootQueryToUsersArgs, context: any, info: GraphQLResolveInfo): Promise<TResult>; // the different is here