# A GraphQL utility to generate Typescript from Schema Definition 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) ## Compatibility | graphql-schema-typescript | graphql | |---------------------------|------------------| |1.6 | ^16.0.0 | |1.5 | ^14.0.0, ^15.0.0 | |1.4 | 0.11~0.13 | ## Features ### Generate Typescript from Schema Definition (1-1 mapping from GQL type to TypeScript) ### Convert GraphQL description into JSDoc, include deprecated directive ### [Generate TypeScripts to support writing resolvers](#type-resolvers) ### [VSCode extension](#https://github.com/liyikun/vscode-graphql-schema-typescript) (credit to [@liyikun](https://github.com/liyikun)) ## Usage ```javascript 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](#https://github.com/TypeStrong/ts-node) to execute it directly * `schema`: your graphql schema * `outputPath`: where the types is generated * `options`: see [GenerateTypescriptOptions](./src/types.ts) ## CLIs * 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 ## Type Resolvers 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: ```gql 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: ```javascript /** * 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 { (parent: TParent, args: RootQueryToUsersArgs, context: any, info: GraphQLResolveInfo): TResult; } ``` In this example, if you are not using [graphql-tools](https://www.npmjs.com/package/graphql-tools), you can still use `RootQueryToUsersResolver` type to make your args type safed. ## Default TParent & TResult 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: ```javascript // smartTParent: true // smartTResult: true // TParent is undefined because it uses the value of 'rootValueType' in options export interface RootQueryToUsersResolver { (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>`. Therefore, another option , `asyncResult`, was implemented. This option basically allow resolver to return promises ```javascript // smartTParent: true // smartTResult: true // asyncResult: true export interface RootQueryToUsersResolver { (parent: TParent, args: RootQueryToUsersArgs, context: any, info: GraphQLResolveInfo): Promise | TResult; // the different is here } ``` ```javascript // in v1.12.11, asyncResult also accept string value 'always', // which will make returns value of resolve functions to be `Promise`, // due to an issue with VSCode that not showing auto completion when returns is a mix of `T | Promise` (see [#17](https://github.com/dangcuuson/graphql-schema-typescript/issues/17)) // smartTParent: true // smartTResult: true // asyncResult: 'always' export interface RootQueryToUsersResolver { (parent: TParent, args: RootQueryToUsersArgs, context: any, info: GraphQLResolveInfo): Promise; // the different is here ```

	Stars	Issues	Version	Updated	Created
apollo-codegen	3,038	387	0.20.2	6 years ago	8 years ago
graphql-schema-typescript	191	24	1.6.1	4 months ago	6 years ago
graphql-zeus	1,896	79	5.3.4	18 days ago	5 years ago
graphqlgen	820	67	0.6.0-rc9	5 years ago	6 years ago
hasura			2.0.1	6 years ago	6 years ago

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