Added option to import custom file types (#53)

* Added option to import custom file types

* Add section to README documenting defaults and describing usage

README.md

@@ -183,6 +183,8 @@ Option | Type | Default | Description
 -|-|-|-
 `nodePath` | String | value of NODE_PATH environment variable | **Intended for use with [react-app-rewire-inline-import-graphql-ast](https://github.com/detrohutt/react-app-rewire-inline-import-graphql-ast)** -- Used to allow resolution of absolute paths to your `.gql`/`.graphql` files. If you already have your `NODE_PATH` variable set in your environment, you don't need to set this option. **Not** currently respected by `#import` syntax.
 `runtime` | Boolean | false | **Enabling this option requires `graphql-tag` to be installed as a peerDependency.** -- Instead of inlining the parsed AST object, which is very large, this option inlines your GraphQL source code along with an import of the `gql` function from `graphql-tag` and parses your GraphQL source code with `gql` at runtime.
+`extensions` | Array | [] | Enables loading GraphQL SDL files that have a custom extension, e.g. '.prisma' 
+
 
 ## For users of create-react-app
 

plugin/index.js

@@ -17,8 +17,11 @@ export default ({ types: t, template }) => ({
       exit(curPath, { opts, file }) {
         const importPath = curPath.node.source.value
         const jsFilename = file.opts.filename
+        let { extensions = [] } = opts
 
-        if (importPath.endsWith('.graphql') || importPath.endsWith('.gql')) {
+        extensions = [...extensions, '.graphql', '.gql']
+
+        if (extensions.some(extension => importPath.endsWith(extension))) {
           if (opts.runtime) {
             try {
               require('graphql-tag')

tests/fixtures/imports/named/extension.js

@@ -0,0 +1 @@
+import extension from '../../shared/extension.graph'

tests/fixtures/shared/extension.graph

@@ -0,0 +1,3 @@
+query named {
+  test
+}

tests/imports.test.js

@@ -127,6 +127,18 @@ describe.each([{ runtime: true }, {}])('plugin options = %j', opts => {
     })
   })
 
+  describe('non-standard extension', () => {
+    test(`import extension from 'extension.graph'`, () => {
+      const { code } = transformWithPlugin('./fixtures/imports/named/extension.js', {
+        ...opts,
+        extensions: ['.graph']
+      })
+      let _graphqlTag, _graphqlTag2, extension
+      eval(code)
+      expect(extension.kind).toBe('Document')
+    })
+  })
+
   describe('single fragment document', () => {
     test(`import frag from '../../shared/fragments/fragment.graphql'`, () => {
       const { code } = transformWithPlugin('./fixtures/imports/fragments/simple.js', opts)