✨ Add support for memo typed with generics (#159)

* ✨ Add support for memo typed with generics

* docs(changeset): Add support for memos typed with generics

Author: danieldelcore

.changeset/shiny-cows-share.md

@@ -0,0 +1,5 @@
+---
+'extract-react-types': minor
+---
+
+Add support for memos typed with generics

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

@@ -396,6 +396,62 @@ Object {
 }
 `;
 
+exports[`TypeScript: memo typed via generic types 1`] = `
+Object {
+  "kind": "generic",
+  "name": Object {
+    "kind": "id",
+    "name": "MyComponent",
+    "type": null,
+  },
+  "value": Object {
+    "kind": "object",
+    "members": Array [
+      Object {
+        "key": Object {
+          "kind": "id",
+          "name": "foo",
+        },
+        "kind": "property",
+        "optional": false,
+        "value": Object {
+          "kind": "string",
+        },
+      },
+    ],
+    "referenceIdName": "MyComponentProps",
+  },
+}
+`;
+
+exports[`TypeScript: memo wrapping forwardRef, both typed via generic types 1`] = `
+Object {
+  "kind": "generic",
+  "name": Object {
+    "kind": "id",
+    "name": "MyComponent",
+    "type": null,
+  },
+  "value": Object {
+    "kind": "object",
+    "members": Array [
+      Object {
+        "key": Object {
+          "kind": "id",
+          "name": "foo",
+        },
+        "kind": "property",
+        "optional": false,
+        "value": Object {
+          "kind": "string",
+        },
+      },
+    ],
+    "referenceIdName": "MyComponentProps",
+  },
+}
+`;
+
 exports[`TypeScript: ts any 1`] = `
 Object {
   "kind": "object",

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

@@ -567,6 +567,40 @@ const TESTS = [
 
     export default MyComponent;
   `
+  },
+  {
+    name: 'memo typed via generic types',
+    typeSystem: 'typescript',
+    code: `
+    import React, { forwardRef, memo } from 'react';
+
+    type MyComponentProps = {
+      foo: string,
+    }
+
+    const MyComponent = memo<MyComponentProps>((props, ref) => {
+      return <span>Foo</span>;
+    });
+
+    export default MyComponent;
+  `
+  },
+  {
+    name: 'memo wrapping forwardRef, both typed via generic types',
+    typeSystem: 'typescript',
+    code: `
+    import React, { forwardRef, memo } from 'react';
+
+    type MyComponentProps = {
+      foo: string,
+    }
+
+    const MyComponent = memo<MyComponentProps>(forwardRef<HTMLElement, MyComponentProps>((props, ref) => {
+      return <span>Foo</span>;
+    }));
+
+    export default MyComponent;
+  `
   }
 ];
 

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

@@ -1,27 +1,31 @@
 import { loadFileSync, resolveImportFilePathSync } from 'babel-file-loader';
+
 export function hasDestructuredDefaultExport(path) {
-  const exportPath = path.get('body').find(bodyPath => {
-    return (
-      bodyPath.isExportNamedDeclaration() &&
-      bodyPath.get('specifiers').filter(n => n.node.exported.name === 'default').length
+  const exportPath = path
+    .get('body')
+    .find(
+      bodyPath =>
+        bodyPath.isExportNamedDeclaration() &&
+        bodyPath.get('specifiers').filter(n => n.node.exported.name === 'default').length
     );
-  });
 
   return Boolean(exportPath);
 }
 
 export function followExports(path, context, convert) {
-  const exportPath = path.get('body').find(bodyPath => {
-    return (
-      bodyPath.isExportNamedDeclaration() &&
-      bodyPath.get('specifiers').filter(n => n.node.exported.name === 'default')
+  const exportPath = path
+    .get('body')
+    .find(
+      bodyPath =>
+        bodyPath.isExportNamedDeclaration() &&
+        bodyPath.get('specifiers').filter(n => n.node.exported.name === 'default')
     );
-  });
 
-  if (!exportPath)
+  if (!exportPath) {
     throw new Error({
       message: 'No export path found'
     });
+  }
 
   try {
     const filePath = resolveImportFilePathSync(exportPath, context.resolveOptions);

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

@@ -1366,6 +1366,7 @@ function exportedComponents(programPath, componentsToFind: 'all' | 'default', co
       components.push({ name, path, component });
       return;
     }
+
     if (path.isClass()) {
       let component = convertReactComponentClass(path, context);
       components.push({ name, path, component });
@@ -1380,7 +1381,7 @@ function exportedComponents(programPath, componentsToFind: 'all' | 'default', co
       const genericTypeParams = path.get('typeParameters');
 
       // Props are the second type arg
-      if (isForwardRef && genericTypeParams && genericTypeParams.node) {
+      if (isForwardRef && genericTypeParams.node) {
         const component = convertReactComponentFunction(
           genericTypeParams,
           context,
@@ -1392,6 +1393,18 @@ function exportedComponents(programPath, componentsToFind: 'all' | 'default', co
         return;
       }
 
+      if (isMemo && genericTypeParams.node) {
+        const component = convertReactComponentFunction(
+          genericTypeParams,
+          context,
+          genericTypeParams.get('params.0')
+        );
+
+        components.push({ name, path, component });
+
+        return;
+      }
+
       // Props typed via function arguments
       const firstArg = path.get('arguments')[0];