Compiling queries with Babel

If you prefer co-locating your GraphQL queries in your Javascript files, you typically use the graphql-tag library to write them. That requires to process the query strings into a GraphQL AST, which will add to the startup time of your application, especially if you have many queries.

To avoid this runtime overhead, you can precompile your queries created with graphql-tag using Babel. Here are two ways you can do this:

1. Using babel-plugin-graphql-tag
2. Using graphql-tag.macro

If you prefer to keep your GraphQL code in separate files (.graphql or .gql) you can use babel-plugin-import-graphql. This plugin still uses graphql-tag under the hood, but transparently. You simply import your operations/fragments as if each were an export from your GraphQL file. This carries the same precompilation benefits as the above approaches.

Using babel-plugin-graphql-tag

This approach will allow you to use the graphql-tag library as usual, and when processing the files with this babel plugin, the calls to that library will be replaced by the precompiled result.

Install the plugin in your dev dependencies:

# with npm
npm install --save-dev babel-plugin-graphql-tag

# or with yarn
yarn add --dev babel-plugin-graphql-tag

Then add the plugin in your .babelrc configuration file:

{
  "plugins": [
    "graphql-tag"
  ]
}

And that's it! All the usages of import gql from 'graphql-tag' will be removed, and the calls to gql will be replaced by the compiled version.Using graphql-tag.macro

This approach is a bit more explicit, since you change all your usages of graphql-tag for graphql-tag.macro, which exports a gql function that you can use the same way as the original one. This macro requires the babel-macros plugin, which will do the same as the previous approach but only on the calls that come from the macro import, leaving regular calls to the graphql-tag library untouched.

Why would you prefer this approach? Mainly because it requires less configuration (babel-macros works with all kinds of macros, so if you already had it installed you don't have to do anything else), and also because of the explicitness. You can read more about the rationale of using babel-macros in this blog post.

To use it, provided that you already have babel-macros installed and configured, you just need to change this:

import gql from 'graphql-tag';

const query = gql`
  query {
    hello {
      world
    }
  }
`;

to this:

import gql from 'graphql-tag.macro'; // <-- Use the macro

const query = gql`
  query {
    hello {
      world
    }
  }
`;

Using babel-plugin-import-graphql

Install the plugin in your dev dependencies:

# with npm
npm install --save-dev babel-plugin-import-graphql
# or with yarn
yarn add --dev babel-plugin-import-graphql

Then add the plugin in your .babelrc configuration file:

{
  "plugins": [
    "import-graphql"
  ]
}

Now any import statements importing from a GraphQL file type will return a ready-to-use GraphQL DocumentNode object.

import React, { Component } from 'react';
import { graphql } from '@apollo/react-hoc';
import myImportedQuery from './productsQuery.graphql';
// or for files with multiple operations:
// import { query1, query2 } from './queries.graphql';
class QueryingComponent extends Component {
  render() {
    if (this.props.data.loading) return <h3>Loading...</h3>;
    return <div>{`This is my data: ${this.props.data.queryName}`}</div>;
  }
}
export default graphql(myImportedQuery)(QueryingComponent);

Fragments

All of these approaches support the use of fragments.

For the first two approaches, you can have fragments defined in a different call to gql (either in the same file or in a different one). You can then include them into the main query using interpolation, like this:

import gql from 'graphql-tag';
// or import gql from 'graphql-tag.macro';
const fragments = {
  hello: gql`
    fragment HelloStuff on Hello {
      universe
      galaxy
    }
  `
};

const query = gql`
  query {
    hello {
      world
      ...HelloStuff
    }
  }
  ${fragments.hello}
`;

With babel-plugin-import-graphql, you can just include your fragment in your GraphQL file along-side whatever uses it, or even import it from a separate file using the #import syntax.

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