graphql-schema-from-json
Guess a GraphQL schema from json data.
Installation
npm install --save graphql-schema-from-json
or
yarn graphql-schema-from-json
Usage
;; const data = posts: id: 1 title: "Lorem Ipsum" views: 254 user_id: 123 id: 2 title: "Sic Dolor amet" views: 65 user_id: 456 users: id: 123 name: "John Doe" id: 456 name: "Jane Doe" comments: id: 987 post_id: 1 body: "Consectetur adipiscing elit" date: '2017-07-03' id: 995 post_id: 1 body: "Nam molestie pellentesque dui" date: '2017-08-17' // Get the schema as a JSON objectconst schema = ; // Print the GQL for this schemaconsole;
Generated Types and Queries
Based on your data, graphql-schema-from-json
will generate a schema with one type per entity, as well as 3 query types and 3 mutation types. For instance for the Post
entity:
type Query { Post(id: ID!): Post allPosts(page: Int, perPage: Int, sortField: String, sortOrder: String, filter: PostFilter): [Post] _allPostsMeta(page: Int, perPage: Int, sortField: String, sortOrder: String, filter: PostFilter): ListMetadata}type Mutation { createPost(data: String): Post updatePost(data: String): Post removePost(id: ID!): Boolean}type Post { id: ID! title: String! views: Int! user_id: ID! User: User Comments: [Comment]}type PostFilter { q: String id: ID title: String views: Int views_lt: Int views_lte: Int views_gt: Int views_gte: Int user_id: ID}type ListMetadata { count: Int!}scalar Date
By convention, graphql-schema-from-json
expects all entities to have an id
field that is unique for their type - it's the entity primary key. The type of every field is inferred from the values, so for instance, Post.title
is a String!
, and Post.views
is an Int!
. When all entities have a value for a field, graphql-schema-from-json
makes the field type non nullable (that's why Post.views
type is Int!
and not Int
).
For every field named *_id
, graphql-schema-from-json
creates a two-way relationship, to let you fetch related entities from both sides. For instance, the presence of the user_id
field in the posts
entity leads to the ability to fetch the related User
for a Post
- and the related Posts
for a User
.
The all*
queries accept parameters to let you sort, paginate, and filter the list of results. You can filter by any field, not just the primary key. For instance, you can get the posts written by user 123
. graphql-schema-from-json
also adds a full-text query field named q
, and created range filter fields for numeric and date fields. The detail of all available filters can be seen in the generated *Filter
type.
GraphQL Usage
Here is how you can use the queries and mutations generated for your data, using Post
as an example:
Query / Mutation | Result |
---|---|
// get a single entity, by id { Post(id: 1) { id title views user_id } } |
{ "data": { "Post": { "id": 1, "title": "Lorem Ipsum", "views": 254, "user_id": 123 } } } |
// include many-to-one relationships { Post(id: 1) { title User { name } } } |
{ "data": { "Post": { "title": "Lorem Ipsum", "User": { "name": "John Doe" } } } } |
// include one-to-many relationships { Post(id: 1) { title Comments { body } } } |
{ "data": { "Post": { "title": "Lorem Ipsum", "Comments": [ { "body": "Consectetur adipiscing elit" }, { "body": "Nam molestie pellentesque dui" }, ] } } } |
// get a list of entities for a type { allPosts { title views } } |
{ "data": { "allPosts": [ { "title": "Lorem Ipsum", views: 254 }, { "title": "Sic Dolor amet", views: 65 } ] } } |
// paginate the results { allPosts(page: 0, perPage: 1) { title views } } |
{ "data": { "allPosts": [ { "title": "Lorem Ipsum", views: 254 }, ] } } |
// sort the results by field { allPosts(sortField: "title", sortOrder: "desc") { title views } } |
{ "data": { "allPosts": [ { "title": "Sic Dolor amet", views: 65 } { "title": "Lorem Ipsum", views: 254 }, ] } } |
// filter the results using the full-text filter { allPosts({ filter: { q: "lorem" }}) { title views } } |
{ "data": { "allPosts": [ { "title": "Lorem Ipsum", views: 254 }, ] } } |
// filter the result using any of the entity fields { allPosts(views: 254) { title views } } |
{ "data": { "allPosts": [ { "title": "Lorem Ipsum", views: 254 }, ] } } |
// number fields get range filters // -lt, _lte, -gt, and _gte { allPosts(views_gte: 200) { title views } } |
{ "data": { "allPosts": [ { "title": "Lorem Ipsum", views: 254 }, ] } } |
Roadmap
- Allow to override the primary key for each entity
- Allow to override the relationship detection
Contributing
Use Prettier formatting and make sure you include unit tests. The project includes a Makefile
to automate usual developer tasks:
make installmake buildmake testmake watchmake format
License
graphql-schema-from-json is licensed under the MIT Licence, sponsored and supported by marmelab.