From f313d9b5967dcc2f6183ca8ff6ce5a4c90e68ca0 Mon Sep 17 00:00:00 2001
From: Michael Bashurov <accounts@saitonakamura.me>
Date: Sat, 27 Feb 2021 11:24:56 +0200
Subject: [PATCH] Allow nullish extends in interfaceish

Otherwise code such as

```ts
t.interfaceDeclaration(
  t.identifier('id'),
  undefined,
  undefined,
  t.objectTypeAnnotation([])
)
```

Will fail when priting with ` TypeError: unknown: Cannot read property 'length' of null`
Despite nullish values being allowed in `t.interfaceDeclaration` definitions
---
 packages/babel-generator/src/generators/flow.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/babel-generator/src/generators/flow.ts b/packages/babel-generator/src/generators/flow.ts
index c59b2518389f4..9bb094698a0a7 100644
--- a/packages/babel-generator/src/generators/flow.ts
+++ b/packages/babel-generator/src/generators/flow.ts
@@ -360,7 +360,7 @@ export function _interfaceish(
 ) {
   this.print(node.id, node);
   this.print(node.typeParameters, node);
-  if (node.extends.length) {
+  if (node.extends && node.extends.length) {
     this.space();
     this.word("extends");
     this.space();