✨ Adds support for React.FC & FC (#183)

* ✨ Adds support for React.FC & FC

* docs(changeset): Adds support for React.FC and FC

Author: danieldelcore

.changeset/tough-crews-share.md

@@ -0,0 +1,5 @@
+---
+'extract-react-types': patch
+---
+
+Adds support for React.FC and FC

packages/extract-react-types/__snapshots__/converters-typescript.test.js.snap

@@ -28,6 +28,69 @@ Object {
 }
 `;
 
+exports[`TypeScript: FC 1`] = `
+Object {
+  "kind": "generic",
+  "name": Object {
+    "kind": "id",
+    "name": "Component",
+    "type": null,
+  },
+  "value": Object {
+    "kind": "object",
+    "members": Array [
+      Object {
+        "key": Object {
+          "kind": "id",
+          "name": "children",
+        },
+        "kind": "property",
+        "optional": false,
+        "value": Object {
+          "kind": "string",
+        },
+      },
+    ],
+    "referenceIdName": "Props",
+  },
+}
+`;
+
+exports[`TypeScript: FC with empty type argument 1`] = `
+Object {
+  "kind": "any",
+  "name": Object {
+    "kind": "id",
+    "name": "Component",
+    "type": null,
+  },
+}
+`;
+
+exports[`TypeScript: FC with inline type argument 1`] = `
+Object {
+  "kind": "object",
+  "members": Array [
+    Object {
+      "key": Object {
+        "kind": "id",
+        "name": "children",
+      },
+      "kind": "property",
+      "optional": false,
+      "value": Object {
+        "kind": "string",
+      },
+    },
+  ],
+  "name": Object {
+    "kind": "id",
+    "name": "Component",
+    "type": null,
+  },
+}
+`;
+
 exports[`TypeScript: React.ComponentType 1`] = `
 Object {
   "kind": "generic",

packages/extract-react-types/converters-typescript.test.js

@@ -65,7 +65,7 @@ const TESTS = [
   `
   },
   {
-    name: 'React.FC',
+    name: 'FC',
     typeSystem: 'typescript',
     code: `
       type Props = {
@@ -78,7 +78,7 @@ const TESTS = [
     `
   },
   {
-    name: 'React.FC with empty type argument',
+    name: 'FC with empty type argument',
     typeSystem: 'typescript',
     code: `
       type Props = {
@@ -91,7 +91,7 @@ const TESTS = [
     `
   },
   {
-    name: 'React.FC with inline type argument',
+    name: 'FC with inline type argument',
     typeSystem: 'typescript',
     code: `
       const Component: FC<{
@@ -101,6 +101,47 @@ const TESTS = [
       export default Component;
     `
   },
+  {
+    name: 'React.FC',
+    typeSystem: 'typescript',
+    code: `
+      import React from 'react';
+
+      type Props = {
+        children: string;
+      };
+
+      const Component: React.FC<Props> = (props) => null;
+
+      export default Component;
+    `
+  },
+  {
+    name: 'React.FC with empty type argument',
+    typeSystem: 'typescript',
+    code: `
+      import React from 'react';
+
+      type Props = {
+        children: string;
+      };
+
+      const Component: React.FC = (props) => null;
+
+      export default Component;
+    `
+  },
+  {
+    name: 'React.FC with inline type argument',
+    typeSystem: 'typescript',
+    code: `
+      const Component: React.FC<{
+        children: string;
+      }> = (props) => null;
+
+      export default Component;
+    `
+  },
   {
     name: 'Direct type assignment',
     typeSystem: 'typescript',

packages/extract-react-types/src/converter.js

@@ -15,7 +15,7 @@ import {
   hasDestructuredDefaultExport,
   matchExported
 } from './export-manager';
-
+import { hasTypeAnnotation } from './utils';
 import * as K from './kinds';
 
 const converters = {};
@@ -1277,13 +1277,8 @@ export function convertComponentExports(componentExports, context) {
     ) {
       let propType;
 
-      // check for a component typed with the `FC<Props>` annotation
-      if (
-        path.parentPath.node.id &&
-        path.parentPath.node.id.typeAnnotation &&
-        path.parentPath.node.id.typeAnnotation.typeAnnotation.typeName.name === 'FC' &&
-        path.parentPath.node.id.typeAnnotation.typeAnnotation.typeParameters
-      ) {
+      // check for a component typed with the `React.FC<Props>` or `FC<Props>` type annotation
+      if (hasTypeAnnotation(path.parentPath, 'React', 'FC')) {
         propType = path.parentPath.get('id.typeAnnotation.typeAnnotation.typeParameters.params.0');
       } else {
         // we have a normal function, assume the props are the first parameter

packages/extract-react-types/src/utils.js

@@ -0,0 +1,20 @@
+/* eslint-disable import/prefer-default-export */
+
+export function hasTypeAnnotation(path, left, right) {
+  if (!path.isVariableDeclarator() || !path.node.id.typeAnnotation) {
+    return false;
+  }
+
+  const { typeName, typeParameters } = path.node.id.typeAnnotation.typeAnnotation;
+
+  if (!typeParameters) return false;
+
+  if (
+    (typeName.left && typeName.left.name === left && typeName.right.name === right) ||
+    ((right && typeName.name === right) || typeName.name === left)
+  ) {
+    return true;
+  }
+
+  return false;
+}