graphql-sequelize


Should be used with dataloader-sequelize to avoid N+1 queries

- Installation
- Resolve helpers
- field helpers
- args helpers

Installation

$ npm install --save graphql-sequelize

graphql-sequelize assumes you have graphql and sequelize installed.

Resolve helpers

``js
import { resolver } from "graphql-sequelize";

resolver(SequelizeModel[, options]);
`

A helper for resolving graphql queries targeted at Sequelize models or associations.
Please take a look at the tests to best get an idea of implementation.

$3

- Automatically converts args to where if arg keys matches model attributes
- Automatically converts an arg named 'limit' to a sequelize limit
- Automatically converts an arg named 'order' to a sequelize order

$3

Relay documentation

$3

The resolver function takes a model as its first (required) argument, but also
has a second options object argument. The available options are:

`js
resolver(SequelizeModel, {
// Whether or not this should return a list. Defaults to whether or not the
// field type is an instance of GraphQLList.
list: false,

// Whether or not relay connections should be handled. Defaults to true.
handleConnection: true,

/**
* Manipulate the query before it's sent to Sequelize.
* @param findOptions {object} - Options sent to Seqeulize model's find function
* @param args {object} - The arguments from the incoming GraphQL query
* @param context {object} - Resolver context, see more at GraphQL docs below.
* @returns findOptions or promise that resolves with findOptions
*/
before: (findOptions, args, context) => {
findOptions.where = { / Custom where arguments / };
return findOptions;
},
/**
* Manipulate the Sequelize find results before it's sent back to the requester.
* @param result {object|array} - Result of the query, object or array depending on list or not.
* @param args {object} - The arguments from the incoming GraphQL query
* @param context {object} - Resolver context, see more at GraphQL docs below.
* @returns result(s) or promise that resolves with result(s)
*/
after: (result, args, context) => {
result.sort(/ Custom sort function /);
return result;
},

/*
* Transfer fields from the graphql context to the options passed to model calls
* Inherits from global resolver.contextToOptions
*/
contextToOptions: {
a: 'a',
b: 'c'
}
});

resolver.contextToOptions = {}; / Set contextToOptions globally /
`

_The args and context parameters are provided by GraphQL. More information
about those is available in their resolver docs._

$3

`js
import {resolver} from 'graphql-sequelize';

let User = sequelize.define('user', {
name: Sequelize.STRING
});

let Task = sequelize.define('task', {
title: Sequelize.STRING
});

User.Tasks = User.hasMany(Task, {as: 'tasks'});

let taskType = new GraphQLObjectType({
name: 'Task',
description: 'A task',
fields: {
id: {
type: new GraphQLNonNull(GraphQLInt),
description: 'The id of the task.',
},
title: {
type: GraphQLString,
description: 'The title of the task.',
}
}
});

let userType = new GraphQLObjectType({
name: 'User',
description: 'A user',
fields: {
id: {
type: new GraphQLNonNull(GraphQLInt),
description: 'The id of the user.',
},
name: {
type: GraphQLString,
description: 'The name of the user.',
},
tasks: {
type: new GraphQLList(taskType),
resolve: resolver(User.Tasks)
}
}
});

let schema = new GraphQLSchema({
query: new GraphQLObjectType({
name: 'RootQueryType',
fields: {
// Field for retrieving a user by ID
user: {
type: userType,
// args will automatically be mapped to where
args: {
id: {
description: 'id of the user',
type: new GraphQLNonNull(GraphQLInt)
}
},
resolve: resolver(User)
},

// Field for searching for a user by name
userSearch: {
type: new GraphQLList(userType),
args: {
query: {
description: "Fuzzy-matched name of user",
type: new GraphQLNonNull(GraphQLString),
}
},
resolve: resolver(User, {
// Custom where clause that fuzzy-matches user's name and
// alphabetical sort by username
before: (findOptions, args) => {
findOptions.where = {
name: { "$like": %${args.query}% },
};
findOptions.order = [['name', 'ASC']];
return findOptions;
},
// Custom sort override for exact matches first
after: (results, args) => {
return results.sort((a, b) => {
if (a.name === args.query) {
return 1;
}
else if (b.name === args.query) {
return -1;
}

return 0;
});
}
})
}
}
})
});

let schema = new GraphQLSchema({
query: new GraphQLObjectType({
name: 'RootQueryType',
fields: {
users: {
// The resolver will use findOne or findAll depending on whether the field it's used in is a GraphQLList or not.
type: new GraphQLList(userType),
args: {
// An arg with the key limit will automatically be converted to a limit on the target
limit: {
type: GraphQLInt
},
// An arg with the key order will automatically be converted to a order on the target
order: {
type: GraphQLString
}
},
resolve: resolver(User)
}
}
})
});
`

field helpers

field helpers help you automatically define a models attributes as fields for a GraphQL object type.

`js
var Model = sequelize.define('User', {
email: {
type: Sequelize.STRING,
allowNull: false
},
firstName: {
type: Sequelize.STRING
},
lastName: {
type: Sequelize.STRING
}
});

import {attributeFields} from 'graphql-sequelize';

attributeFields(Model, {
// ... options
exclude: Array, // array of model attributes to ignore - default: []
only: Array, // only generate definitions for these model attributes - default: null
globalId: Boolean, // return an relay global id field - default: false
map: Object, // rename fields - default: {}
allowNull: Boolean, // disable wrapping mandatory fields in GraphQLNonNull - default: false
commentToDescription: Boolean, // convert model comment to GraphQL description - default: false
cache: Object, // Cache enum types to prevent duplicate type name error - default: {}
});

/*
{
id: {
type: new GraphQLNonNull(GraphQLInt)
},
email: {
type: new GraphQLNonNull(GraphQLString)
},
firstName: {
type: GraphQLString
},
lastName: {
type: GraphQLString
}
}
*/

userType = new GraphQLObjectType({
name: 'User',
description: 'A user',
fields: Object.assign(attributeFields(Model), {
// ... extra fields
})
});
`


$3

attributeFields uses the graphql-sequelize typeMapper to map Sequelize types to GraphQL types. You can supply your own
mapping function to override this behavior using the mapType export.

`js
var Model = sequelize.define('User', {
email: {
type: Sequelize.STRING,
allowNull: false
},
isValid: {
type: Sequelize.BOOLEAN,
allowNull: false
}
});

import {attributeFields,typeMapper} from 'graphql-sequelize';
typeMapper.mapType((type) => {
//map bools as strings
if (type instanceof Sequelize.BOOLEAN) {
return GraphQLString
}
//use default for everything else
return false
});

//map fields
attributeFields(Model);

/*
{
id: {
type: new GraphQLNonNull(GraphQLInt)
},
email: {
type: new GraphQLNonNull(GraphQLString)
},
isValid: {
type: new GraphQLNonNull(GraphQLString)
},
}
*/

`

$3

attributeFields accepts a `map` option to customize the way the attribute fields are named. The `map` option accepts
an object or a function that returns a string.

`js

var Model = sequelize.define('User', {
email: {
type: Sequelize.STRING,
allowNull: false
},
firstName: {
type: Sequelize.STRING
},
lastName: {
type: Sequelize.STRING
}
});

attributeFields(Model, {
map:{
email:"Email",
firstName:"FirstName",
lastName:"LastName"
}
});

/*
{
id: {
type: new GraphQLNonNull(GraphQLInt)
},
Email: {
type: new GraphQLNonNull(GraphQLString)
},
FirstName: {
type: GraphQLString
},
LastName: {
type: GraphQLString
}
}
*/

attributeFields(Model, {
map:(k) => k.toLowerCase()
});

/*
{
id: {
type: new GraphQLNonNull(GraphQLInt)
},
email: {
type: new GraphQLNonNull(GraphQLString)
},
firstname: {
type: GraphQLString
},
lastname: {
type: GraphQLString
}
}
*/

`

$3

GraphQL enum types only support ASCII alphanumeric characters, digits and underscores with leading non-digit.
If you have other characters, like a dash (-) in your Sequelize enum types,
they will be converted to camelCase. If your enum value starts from a digit, it
will be prepended with an underscore.

For example:

- foo-bar becomes fooBar

- 25.8 becomes _258

$3

If you have Sequelize.VIRTUAL attributes on your sequelize model, you need to explicitly set the return type and any field dependencies via new Sequelize.VIRTUAL(returnType, [dependencies ... ]).

For example, fullName here will not always return valid data when queried via GraphQL:
`js
firstName: { type: Sequelize.STRING },
lastName: { type: Sequelize.STRING },
fullName: {
type: Sequelize.VIRTUAL,
get: function() { return ${this.firstName} ${this.lastName}; },
},
`

To work properly fullName needs to be more fully specified:

`js
firstName: { type: Sequelize.STRING },
lastName: { type: Sequelize.STRING },
fullName: {
type: new Sequelize.VIRTUAL(Sequelize.STRING, ['firstName', 'lastName']),
get: function() { return ${this.firstName} ${this.lastName}; },
},
`

args helpers

$3

defaultArgs(Model) will return an object containing an arg with a key and type matching your models primary key and
the "where" argument for passing complex query operations described here

`js
var Model = sequelize.define('User', {

});

defaultArgs(Model);

/*
{
id: {
type: new GraphQLNonNull(GraphQLInt)
}
}
*/

var Model = sequelize.define('Project', {
project_id: {
type: Sequelize.UUID
}
});

defaultArgs(Model);

/*
{
project_id: {
type: GraphQLString
},
where: {
type: JSONType
}
}
*/
`

If you would like to pass "where" as a query variable - you should pass it as a JSON string and declare its type as SequelizeJSON:

`
/ with GraphiQL /
// request
query($where: SequelizeJSON) {
user(where: $where) {
name
}
}

// query variables


JSON doesn't allow single quotes, so you need to use escaped double quotes in your JSON string


{
"where": "{\"name\": {\"like\": \"Henry%\"}}"
}
`

$3

defaultListArgs will return an object like:

`js
{
limit: {
type: GraphQLInt
},
order: {
type: GraphQLString
},
where: {
type: JSONType
}
}
`

Which when added to args will let the resolver automatically support limit and ordering in args for graphql queries.
Should be used with fields of type GraphQLList.

`js
import {defaultListArgs} from 'graphql-sequelize'

args: Object.assign(defaultListArgs(), {
// ... additional args
})
`

order expects a valid field name and will sort ASC by default. For DESC you would prepend reverse: to the field name.


`
/ with GraphiQL /
// users represents a GraphQLList of type user

query($limit: Int, $order: String, $where: SequelizeJSON) {
users(limit: $limit, order: $order, where: $where) {
name
}
}

// query variables
{
"order": "name" // OR "reverse:name" for DESC
}
``