From 8bd104f3c4e2683479a1d263c00ba648fa642c75 Mon Sep 17 00:00:00 2001
From: Michael Bashurov <accounts@saitonakamura.me>
Date: Sat, 27 Feb 2021 12:12:55 +0200
Subject: [PATCH] Fix a bug with invalid print output when empty array is
 passed to t.tsInterfaceDeclaration

If you pass an empty array as `extends` in `t.tsInterfaceDeclaration` you'll get an invalid code printed

```ts
t.tsInterfaceDeclaration(
  t.identifier('x'),
  undefined,
  [],
  t.tsInterfaceBody([])
)
```

You will get
```ts
interface A extends {}
```

Which is an invalid TS, this PR fixes that
---
 packages/babel-generator/src/generators/typescript.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/babel-generator/src/generators/typescript.ts b/packages/babel-generator/src/generators/typescript.ts
index 14375b0beac5..f0284d824c9d 100644
--- a/packages/babel-generator/src/generators/typescript.ts
+++ b/packages/babel-generator/src/generators/typescript.ts
@@ -435,7 +435,7 @@ export function TSInterfaceDeclaration(
   this.space();
   this.print(id, node);
   this.print(typeParameters, node);
-  if (extendz) {
+  if (extendz?.length > 0) {
     this.space();
     this.word("extends");
     this.space();