From fc468a582bed1bce978df6adba9beb0c969285da Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Miroslav=20Jona=C5=A1?= <missing.manual@gmail.com>
Date: Mon, 30 Oct 2023 16:57:59 +0100
Subject: [PATCH] fix(linter): fix flat config migration (#19742)

---
 packages/eslint/src/generators/init/init-migration.ts  |  1 -
 .../src/generators/utils/flat-config/ast-utils.ts      | 10 ++++++++--
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/packages/eslint/src/generators/init/init-migration.ts b/packages/eslint/src/generators/init/init-migration.ts
index 918d54023ed7d..a4da8e7804d59 100644
--- a/packages/eslint/src/generators/init/init-migration.ts
+++ b/packages/eslint/src/generators/init/init-migration.ts
@@ -99,7 +99,6 @@ function migrateEslintFile(projectEslintPath: string, tree: Tree) {
         'plugin:@nrwl/typescript',
         'plugin:@nrwl/javascript',
       ]);
-      console.warn('Flat eslint config is not supported yet for migration');
       tree.write(projectEslintPath, config);
     } else {
       updateJson(tree, projectEslintPath, (json) => {
diff --git a/packages/eslint/src/generators/utils/flat-config/ast-utils.ts b/packages/eslint/src/generators/utils/flat-config/ast-utils.ts
index 6e74612d62161..9da68e403799e 100644
--- a/packages/eslint/src/generators/utils/flat-config/ast-utils.ts
+++ b/packages/eslint/src/generators/utils/flat-config/ast-utils.ts
@@ -335,18 +335,24 @@ export function addBlockToFlatConfigExport(
   });
   const insert = printer.printNode(ts.EmitHint.Expression, config, source);
   if (options.insertAtTheEnd) {
+    const index =
+      exportsArray.length > 0
+        ? exportsArray.at(exportsArray.length - 1).end
+        : exportsArray.pos;
     return applyChangesToString(content, [
       {
         type: ChangeType.Insert,
-        index: exportsArray[exportsArray.length - 1].end,
+        index,
         text: `,\n${insert}`,
       },
     ]);
   } else {
+    const index =
+      exportsArray.length > 0 ? exportsArray.at(0).pos : exportsArray.pos;
     return applyChangesToString(content, [
       {
         type: ChangeType.Insert,
-        index: exportsArray[0].pos,
+        index,
         text: `\n${insert},`,
       },
     ]);