graphql.js: lightweight graphql client

Lightest GraphQL client with intelligent features.


> Originally inspired by Robert Mosolgo's blog post

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- Too small, 4k gzipped.
- No dependencies, plain vanilla JavaScript.
- Plug & Play.
- Isomorphic.
- Runs on most browsers.
- You don't need to install Node.js ecosystem on your computer.
- Query merging to reduce request number.

Overview

GraphQL is based on a very simple HTTP transaction, which sends a request to an endpoint
with query and variables.

Many libraries require _complex stacks_ to make that simple request.
In any project you don't use React, Relay, you'll need a simpler
client which manages your query and makes a simple request.

``js
// Connect...
var graph = graphql("/graphql")

// Prepare...
graph.fragment({
user: on User {
id,
name
}
})

const allUsers = graph(query { allUsers { ...user } })

const createUser = graph(mutation (@autodeclare) {
createUser($firstName, $lastName) { ...user }
})

await createUser({
firstName: "John",
lastName: "Doe"
})

const users = await allUsers()

console.log(users)
// {
// "allUsers": [{ "id": 1, "name": "John Doe" }]
// }
`

Installation

You can download graphql.js directly, or you can use Bower or NPM.

#### CDN

`html

`

#### Download for Browser

- Development Version - 12kb
- Production Version - 6kb

#### Using NPM
`bash
npm install graphql.js --save

or

yarn add graphql.js
`

#### Using with Rails Asset Pipeline

You can use GraphQL.js with Rails Asset Pipeline using graphqljs-rails.

Using

GraphQL.js is isomorphic. You can use it in both browser and Node.js.

#### Use in Browser

`html

`

#### Use in Node.js

`js
var graphql = require('graphql.js')
`

Or using import
`js
import graphql from 'graphql.js'
`

Connection

Create a simple connection to your GraphQL endpoint.

`js
var graph = graphql("http://localhost:3000/graphql", {
method: "POST", // POST by default.
headers: {
// headers
"Access-Token": "some-access-token"
// OR "Access-Token": () => "some-access-token"
},
fragments: {
// fragments, you don't need to say fragment name.
auth: "on User { token }",
error: "on Error { messages }"
}
})
`

Executing Queries and Mutations

graph will be a simple function that accepts query and variables as parameters.

`js
graph(query ($email: String!, $password: String!) {
auth(email: $email, password: $password) {
... auth # if you use any fragment, it will be added to the query.
... error
}
}, {
email: "john@doe.com",
password: "my-super-password"
}).then(function (response) {
// response is originally response.data of query result
console.log(response)
}).catch(function (error) {
// response is originally response.errors of query result
console.log(error)
})
`

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You can prepare queries for lazy execution. This will allow you to reuse your queries with
different variables without any hassle.

`js
var login = graph(query ($email: String!, $password: String!) {
auth(email: $email, password: $password) {
... on User {
token
}
}
})

// Call it later...
login({
email: "john@doe.com",
password: "my-super-password"
})
`

#### Direct Execution with .run and ES6 Template Tag

If your query doesn't need any variables, it will generate a lazy execution query by default.
If you want to run your query immediately, you have three following options:

`js
// 1st option. create and run function.
graph(...)()
graph.query(...)()
graph.mutate(...)()
//...

// 2nd option. create and run function with run method.
graph.run(...)
graph.query.run(...)
graph.mutate.run(...)

// 3rd option. create and run function with template tag.
graph...
graph.query...
graph.mutate...
`

> I don't recommend using this. Using it too much may break DRY. Use lazy execution as much as possible.

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You can prefix your queries by simply calling helper methods: .query, .mutate or .subscribe

`js
var login = graph.query(($email: String!, $password: String!) {
auth(email: $email, password: $password) {
... on User {
token
}
}
})

var increment = graph.mutateincrement { state }
var onIncrement = graph.subscribeonIncrement { state }
`

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Declaring primitive-typed (String, Int, Float, Boolean) variables in query were a
little bothering to me. That's why I added an @autodeclare keyword or {declare: true} setting to the processor.
It detects types from the variables and declares them in query automatically.

`js
var login = graph.query((@autodeclare) {
auth(email: $email, password: $password) {
... on User {
token
}
}
})

login({
email: "john@doe.com", // It's String! obviously.
password: "my-super-password" // It is, too.
})
`

This will create following query:

`graphql
query ($email: String!, $password: String!) {
auth(email: $email, password: $password) {
... on User {
token
}
}
}
`

You can also pass {declare: true} option to the .query, .mutate and .subscribe helper:

`js
var login = graph.query(auth(email: $email, password: $password) {
... on User {
token
}
}, {declare: true})
`

This will also create the same query above.

#### Detecting IDs

Variable names with matching /_id/i pattern will be declared as ID type. Following examples will be declared as IDs:

- id: 1 will be declared as $id: ID!
- post_id: "123af" will be declared as $post_id: ID!
- postID: 3 will be declared as $postID: ID!
- postId: 4 will be declared as $postId: ID!

You can disable auto ID declaration by adding an ! to the end of the variable name:

- id!: 1 will be declared as $id: Int!
- post_id!: "123af" will be declared as $post_id: String!

And, explicitly given types are prioritized.

- postID!CustomId: 3 will be declared as $postID: CustomId!
- postId!UUID: 4 will be declared as $postId: UUID!

`js
var userById = graph.query((@autodeclare) {
user(id: $id) {
email
}
})

userById({
id: 15
})
`

The example above will generate following query:

`graphql
query ($id: ID!) {
user(id: $id) {
email
}
}
`

#### Solving Integer and Float Problem

Let's say you have a rating query that accepts an argument with a Float argument named rating.
GraphQL.js will declare 10 value as Integer since it casts using value % 1 === 0 ? 'Int' : 'Float' check.

`js
var rate = graph.query((@autodeclare) {
rating(rating: $rating) {
rating
}
})

rate({
rating: 10
})
`

In this case, you must use ! mark to force your type to be Float as below:

`js
rate({
"rating!Float": 10
})
`

This will bypass the casting and declare rating as Float.

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Beside you can pass {declare: true} to helpers:

`js
graph.query("auth(email: $email, password: $password) { token }", {declare: true})
`

Also you can enable auto declaration to run by default using alwaysAutodeclare setting.

`js
var graph = graphql("http://localhost:3000/graphql", {
alwaysAutodeclare: true
})
`

After you enable alwaysAutodeclare option, your methods will try to detect types of variables and declare them.

`js
// When alwaysAutodeclare is true, you don't have to pass {declare: true} option.

graph.query("auth(email: $email, password: $password) { token }")
`

#### Auto Declaring Custom Types

You can define custom types when defining variables by using a simple "variable!Type" notation.
It will help you to make more complex variables:

`js
var register = graph.mutate((@autodeclare) {
userRegister(input: $input) { ... }
})

register({
// variable name and type.
"input!UserRegisterInput": { ... }
})
`

This will generate following query:

`graphql
mutation ($input: UserRegisterInput!) {
userRegister(input: $input) { ... }
}
`

Fragments

Fragments make your GraphQL more DRY and improves reusability. With .fragment method, you'll
manage your fragments easily.

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While constructing your endpoint, you can predefine all of your fragments.

`js
var graph = graphql("/graphql", {
fragments: {
userInfo: on User { id, name, surname, avatar }
}
})
`

And you can use your fragments in your queries. The query will pick your fragments and
will add them to the bottom of your query.

`js
graph.query({ allUsers { ...userInfo } })
`

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You can nest your fragments to keep them organized/namespaced.

`js
var graph = graphql("/graphql", {
fragments: {
user: {
info: on User { id, name, surname, avatar }
}
}
})
`

Accessing them is also intuitive:

`js
graph.query({ allUsers { ...user.info } })
`

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You can reuse fragments in your fragments.

`js
graph.fragment({
user: "on User {name, surname}",
login: {
auth: "on User {token, ...user}"
}
})
`

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You can also add fragments lazily. So you can use your fragments more modular.

`js
// Adds a profile fragment
graph.fragment({
profile: on User {
id
name(full: true)
avatar
}
})

var allUsers = graph.query({
allUsers {
... profile
}
})

allUsers().then(...)
`

Also you can add nested fragments lazily, too:

`js
graph.fragment({
login: {
error: on LoginError {
reason
}
}
})

graph.fragment({
something: {
error: on SomeError {
messages
}
}
})

graph.query({ login {... login.error } })
graph.query({ something {... something.error } })
`

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You can call fragment string by using .fragment method. You have to pass path string to get the fragment.

`js
graph.fragment('login.error')
`

This will give you the matching fragment code:

`graphql
fragment login_error on LoginError {
reason
}
`

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You can use fragments lazily using ES6 template tag queries.

`js
var userProfileToShow = graph.fragment('user.profile')

graphquery { ... ${userProfileToShow} }
`

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You can create queries using .ql ES6 template tag.

`js
// Add some fragments...
graph.fragment({
username: {
user: on User {
username
},
admin: on AdminUser {
username,
administrationLevel
}
}
})

// Get any fragment with its path...
var admin = graph.fragment('username.admin')

// Build your query with using fragment paths or dynamic template variables.
var query = graph.qlquery {
...username.user
...${admin}
}

// Use query anywhere...
$.post("/graphql", {query: query}, function (response) { ... })
`

graph.ql will generate this query string:

`graphql
query {
... username_user
... username_admin
}

fragment username_user on User {
username
}

fragment username_admin on AdminUser {
username,
administrationLevel
}
`

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!merge

> This GIF shows a before/after case to make an example how query merging changes the performance.

graphql.js supports query merging that allows you to collect all the requests into one request.

Assume we've these queries on server, define them just like before we do:
`js
var fetchPost = graph.query({
post(id: $id) {
id
title
text
}
})

var fetchComments = graph.query({
commentsOfPost: comments(postId: $postId) {
comment
owner {
name
}
}
})
`

Normally, we make requests as following:

`js
var postId = 123

// This will send a request.
fetchPost({ id: postId }).then(function (response) {
console.log(response.post)
})

// This also will send a request.
fetchComments({ postId: postId }).then(function (response) {
console.log(response.commentsOfPost)
})
`

This will make two requests:

!ss1

Use .merge(mergeName, variables) command to put them into a merge buffer:

`js
var postId = 123

// This won't send a request.
fetchPost.merge('buildPage', { id: postId }).then(function (response) {
console.log(response.post)
})

// This also won't send a request.
fetchComments.merge('buildPage', { postId: postId }).then(function (response) {
console.log(response.commentsOfPost)
})
`

These will create a buffer with buildPage name, and append the queries to that buffer. You need to use commit(mergeName) to merge the buffer and send to the server, the response will be consolidated:

`js
// This will send a merged request:
graph.commit('buildPage').then(function (response) {
// All base fields will be in response return.
console.log(response.post)
console.log(response.commentsOfPost)
})
`

And this will create only one request:

!ss2

This will create the following merged query generated by graphql.js:

`graphql
query ($merge024533__id: ID!, $merge141499__postId: ID!) {
merge024533_post: {
post(id: $merge024533__id) {
id
title
text
}
}
merge141499_commentsOfPost: {
comments(postId: $merge141499__postId) {
comment
owner {
name
}
}
}
}
`

And variables will be generated, too:

`js
{
"merge024533__id": 123,
"merge141499__postId": 123
}
`

> The merge{number} aliases won't be passed into your responses, since they will be used for initial seperation.

> ⚠️ Important Restriction: You cannot use multiple root fields using query merging.
> ⚠️ Important Restriction: Autodeclaration is on by default, do not use alwaysAutodeclare: true.

Debugging

You can pass debug: true to options parameter to get a console output looks like following:

`
[graphql]: POST http://localhost:3000/graphql
QUERY: query ($email: String!, $password: String!) {
auth(email: $email, password: $password) {
.. login_auth
}
}

fragment info on User { hasPin }
fragment login_auth on User { token, ...info }

VARIABLES: {
"email": "john@doe.com",
"password": "123123"
}

sending as form url-data
`

Advanced

Create a GraphQLProvider.js.

`js
import graphql from 'graphql.js';

/ eslint-disable no-underscore-dangle /
export default {
install(Vue, url, options) {
Vue.mixin({
created() {
this._graph = graphql(url, options);
},
});
Object.defineProperty(Vue.prototype, '$graph', {
get() {
return this._graph;
},
});
},
};
`

And then you can use this with your Vue app:

`js
import Vue from 'vue';
import GraphQLProvider from './GraphQLProvider';

Vue.use(GraphQLProvider, 'http://localhost:3000/graphql', {
headers: {
// headers...
},
});

// ... in your Vue VM
data() {
return {
hello: '',
};
},
methods: {
makeSomeQuery() {
this.$graph.query({hello}).then(response => {
this.hello = response.hello;
});
},
}
`

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As default, GraphQL.js makes a POST request. But you can change the behavior by setting asJSON.

`js
var graph = graphql("http://localhost:3000/graphql", {
asJSON: true
});
`


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graphql-tag converts GraphQL query strings to AST. You can use graphql-tag with GraphQL.js

`js
graph.query(gqlquery { name })
`

> Using graphql-tag will not allow you to use _auto declaration_ and _nested fragments_ syntaxes since these are not valid query syntax for GraphQL but only for this library.

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You can change url anywhere with setUrl method.

`js
var graph = graphql("http://localhost:3000/graphql", {
asJSON: true
});

// Change url
graph.setUrl('http://www.example.com')

// Run query
graph.query({ name })
`

---

Todo App Example

A CRUD ToDo app example code to show how to use GraphQL.js. An implementation can be found at f/graphql.js-demo

`js
var graph = graphql("/graphql", {
alwaysAutodeclare: true,
fragments: {
todo: on Todo {
id
text
isCompleted
}
}
})

function getTodos() {
return graph.query.run(allTodos {
...todo
})
}

function addTodo(text) {
return graph.mutate(todoAdd(text: $text) {
...todo
}, {
text: text
})
}

function setTodo(id, isCompleted) {
return graph.mutate(todoComplete(
id: $id,
status: $isCompleted
) {
...todo
}, {
id: id,
isCompleted: isCompleted
})
}

function removeTodo(id) {
return graph.mutate(todoRemove(
id: $id
) {
...todo
}, {
id: id
})
}
``

License

MIT License

Copyright (c) 2018 Fatih Kadir Akın

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.