@grafoo/react

Grafoo React Bindings

Install

$ npm i @grafoo/{core,react} && npm i -D @grafoo/babel-plugin

Setup

Assuming you already have babel installed, the only additional step required to build an application with Grafoo is to configure @grafoo/babel-plugin. The options it accepts are idFields - the fields Grafoo will take to build unique identifiers, and schema, which is a relative path to your schema file.

{
  "plugins": [
    [
      "@grafoo/babel-plugin",
      {
        "schema": "schema.graphql",
        "idFields": ["id"]
      }
    ]
  ]
}

API

Provider

Provider receives a single client instance prop that will be consumed by the Consumer components.

import React from "react";
import createClient from "@grafoo/core";
import { Provider } from "@grafoo/react";

function fetchQuery(query, variables) {
  const init = {
    method: "POST",
    body: JSON.stringify({ query, variables }),
    headers: {
      "content-type": "application/json"
    }
  };

  return fetch("http://some.graphql.api", init).then(res => res.json());
}

const client = createClient(fetchQuery);

export default function App() {
  return (
    <Provider client={client}>
      <SomeComponent />
    </Provider>
  );
}

Consumer

Consumer is the component that performs query requests to your GraphQL API. It accepts the following props:

Name	Type	Default	Required	Descrition
query	object	-	false	a query created with @grafoo/core/tag
variables	object	-	false	a GraphQL variables object for the query prop
mutations	object	-	false	a map of mutations (description below)
skip	boolean	false	false	whether Consumer should skip the query request initially
children	function	-	false	a render function (description below)

Render parameter

The Consumer render function takes as parameter an object with the following props:

Name	type	Descrition
client	object	the client instance
load	function	a method to execute a query with the query prop
loading	boolean	whether the client is executing a query or not
loaded	boolean	whether the query data is already cached
errors	string[]	an array of GraphQL errors from a failed request to your API

The remaining props are:

• the data fetched by the client and shaped according to your query
• mutation functions generated by the mutations object prop

Example

import React from "react";
import gql from "@grafoo/core/tag";
import { Consumer } from "@grafoo/react";

const ALL_POSTS = gql`
  query getPosts($orderBy: PostOrderBy) {
    allPosts(orderBy: $orderBy) {
      title
      content
      createdAt
      updatedAt
    }
  }
`;

export default function Posts() {
  return (
    <Consumer query={ALL_POSTS} variables={{ orderBy: "createdAt_DESC" }}>
      {({ client, load, loaded, loading, errors, allPosts }) => (
        <h1>
          <marquee>👆 do whatever you want with the variables above 👆</marquee>
        </h1>
      )}
    </Consumer>
  );
}

Mutations

The mutations prop is a map of mutation objects that are shaped like so:

const createPost = {
  query: CREATE_POST_MUTATION,
  optimisticUpdate: ({ allPosts }, variables) => ({
    allPosts: [{ ...variables.postInput, id: "tempID" }, ...allPosts]
  }),
  update: ({ allPosts }, response) => ({
    allPosts: allPosts.map(p => (p.id === "tempID" ? response.post : p))
  })
};

const mutations = { createPost };

A mutation object receives the following props:

Name	Type	Required	Descrition
query	object	true	a mutation query created with @grafoo/core/tag
update	function	false	updates the cache when a request is completed (description below)
optimisticUpdate	function	false	updates the cache before a request is completed (description below)

Each mutation will generate a single function that accepts a GraphQL variables object as argument and return a promise that will resolve with the mutation data or reject with GraphQL errors.

type MutationFn = (variables: Variables) => Promise<MutationResponse>;

Mutation query dependency

Important to notice that to update the cache update and optimistUpdate hooks depend on a query and it's variables object props (so they need be declared in the Consumer). If you need to perform a mutation but updating the cache is not strictly important you can just use the mutation promise resolved data or use the client instance directly.

update

type UpdateFn = (query: QueryData, response: MutationResponse) => CacheUpdate;

The mutation update function is resposible to update the cache when the request is completed. It receives as paremeters an object containing the data from the query it depends upon and the mutation response sent by the server. update return type is an object that describes the changes to be made to the cache.

optimisticUpdate

type OptimistcUpdateFn = (query: QueryData, variables: Variables) => CacheUpdate;

In modern UIs it's to be expected that every user interaction occur in a fraction of seconds. optimisticUpdate responsability is to skip the mutation network roundtrip and update the cache instantaneously, making sure such interactions are as fast as they can be. optimisticUpdate as in update takes as first paremater the depedent query data. As second paremater it receives the variables object with which it's correpondent generated mutation function was called. And again it should return an object that describes the changes to be made to cache.

If you want to perform an optimitic update you have to make sure that the data you are inserting contains the field or fields to extract a unique identifier. For instance, say @grafoo/babel-plugin idFields option is set to insert a property id. Is to be expected that your update has that field mocked.

Example

import React from "react";
import gql from "@grafoo/core/tag";
import { Consumer } from "@grafoo/react";

const ALL_POSTS = gql`
  query getPosts($orderBy: PostOrderBy) {
    allPosts(orderBy: $orderBy) {
      title
      content
      createdAt
      updatedAt
    }
  }
`;

const CREATE_POST = gql`
  mutation createPost($content: String, $title: String, $authorId: ID) {
    createPost(content: $content, title: $title, authorId: $authorId) {
      title
      content
      createdAt
      updatedAt
    }
  }
`;

const mutations = {
  createPost: {
    query: CREATE_POST,
    optimisticUpdate: ({ allPosts }, variables) => ({
      allPosts: [{ ...variables, id: "tempID" }, ...allPosts]
    }),
    update: ({ allPosts }, data) => ({
      allPosts: allPosts.map(p => (p.id === "tempID" ? data.createPost : p))
    })
  }
};

const submit = mutate => event => {
  event.preventDefault();

  const { title, content } = event.target.elements;

  mutate({ title: title.value, content: content.value }).then(mutationData => {
    console.log(mutationData);
  });
};

export default function PostForm() {
  return (
    <Consumer query={ALL_POSTS} mutations={mutations}>
      {({ createPost }) => (
        <form onSubmit={submit(createPost)}>
          <input name="title" />
          <textarea name="content" />
          <button>submit</button>
        </form>
      )}
    </Consumer>
  );
}

LICENSE

MIT