reason-apollo

Reason-apollo

Easily use the Apollo Client 2 with Reason

Install and setup

Install

yarn add reason-apollo

# Add graphql_ppx
yarn add --dev graphql_ppx

# Add JS dependencies
yarn add react-apollo apollo-client apollo-cache-inmemory apollo-link apollo-link-context apollo-link-error apollo-link-http graphql graphql-tag

bsconfig

Add reason-apollo to your bs-dependencies and graphql_ppx/ppx to your ppx_flags

bsconfig.json

"bs-dependencies": [
  "reason-react",
  "reason-apollo"
],
"ppx-flags": [
    "graphql_ppx/ppx"
]

send introspection query

This will generate a graphql_schema.json which will be used to safely type your GraphQL queries/mutations.

yarn send-introspection-query http://my-api.example.com/api

Why reason-apollo?

Watch it's usage in this video:

Usage

Create the Apollo Client

Client.re

/* Create an InMemoryCache */
let inMemoryCache = ApolloInMemoryCache.createInMemoryCache(());

/* Create an HTTP Link */
let httpLink =
 ApolloLinks.createHttpLink(~uri="http://localhost:3010/graphql", ());

let instance = ReasonApollo.createApolloClient(
 ~link=httpLink, 
 ~cache=inMemoryCache, 
 ()
);

ApolloProvider

Index.re

  /* 
    Enhance your application with the `ReasonApollo.Provider` 
    passing him your client instance 
  */
  ReactDOMRe.renderToElementWithId(
    <ReasonApollo.Provider client=Client.instance>
        <App />
    </ReasonApollo.Provider>
  , "index");

Query

MyComponent.re

/* Create a GraphQL Query by using the graphql_ppx */ 
module GetPokemon = [%graphql {|
  query getPokemon($name: String!){
      pokemon(name: $name) {
          name
      }
  }
|}]; 

module GetPokemonQuery = ReasonApollo.CreateQuery(GetPokemon);

let make = (_children) => {
/* ... */,
render: (_) => {
  let pokemonQuery = PokemonQuery.make(~name="Pikachu", ());
  <GetPokemonQuery variables=pokemonQuery##variables>
    ...(({result}) => {
      switch result {
         | NoData => <div> (Utils.ste("No Data")) </div>
         | Loading => <div> (Utils.ste("Loading")) </div>
         | Error(error) => <div> (Utils.ste(error)) </div>
         | Data(response) => <div> (Utils.ste(response##pokemon##name)) </div>
      }
    })
  </GetPokemonQuery>
}
}

Mutation

MyMutation.re

module AddPokemon = [%graphql {|
  mutation addPokemon($name: String!) {
      addPokemon(name: $name) {
          name
      }
  }
|}];

module AddPokemonMutation = ReasonApollo.CreateMutation(AddPokemon);

let make = (_children) => {
/* ... */,
render: (_) => {  
  <AddPokemonMutation>
    ...((
      mutation /* Mutation to call */, 
      _ /* Result of your mutation */
    ) => {
      let dic = Js.Dict.empty();
      Js.Dict.set(dic, "name", Js.Json.string("Bob"));
      let newPokemon = Js.Json.object_(dic);

      <div>
        <button onClick=((_mouseEvent) => {
            mutation({
                "variables": Js.Nullable.return(newPokemon),
                "refetchQueries": [|"getAllPokemons"|]
            }) |> ignore;
          })> 
          (Utils.ste("Add Pokemon")) 
        </button>
      </div>
    })
  </AddPokemonMutation>
}
}

ApolloConsumer

If you simply wan't to have access to the ApolloClient, you can use the ApolloConsumer

<ApolloConsumer>
  ...((apolloClient) => {
    /* We have access to the client! */
  })
</ApolloConsumer>

FAQ

I've added the schema file, but my build fails saying it couldn't find it

In some cases, it seems like there are some differences between the provided send-introspection-query and output from tools you might be using to download the schema (such as apollo-codegen or graphql-cli). If your build is failing, please make sure to try with the provided script. In your project root, run:

$ yarn send-introspection-query <url>