From 30bb5a58bda9244ce169ce50792e396582e8c0d2 Mon Sep 17 00:00:00 2001
From: Rob Hogan <robhogan@meta.com>
Date: Mon, 22 Jun 2026 04:41:28 -0700
Subject: [PATCH] Flow: add `decodedMap` to Babel type definitions

Summary:
Adds missing types for `babel/generator`'s `result.decodedMap`, added to Babel in https://github.com/babel/babel/pull/14497 (v7.17.10)

https://babeljs.io/docs/babel-generator/#result

We'll use this in Metro for more efficient source map generation.

Changelog: [Internal]

Reviewed By: GijsWeterings

Differential Revision: D109247419
---
 flow-typed/npm/babel_v7.x.x.js | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/flow-typed/npm/babel_v7.x.x.js b/flow-typed/npm/babel_v7.x.x.js
index 4da72d6b7d54..abba5ac2cb69 100644
--- a/flow-typed/npm/babel_v7.x.x.js
+++ b/flow-typed/npm/babel_v7.x.x.js
@@ -28,6 +28,24 @@ type _BabelSourceMapSegment = {
   ...
 };
 
+// A "decoded" source map (as produced by `@jridgewell/gen-mapping`), grouped by
+// generated line. Segment fields are all 0-based: generated column, source
+// index, source line, source column, name index.
+type _BabelDecodedSourceMapSegment =
+  | [number]
+  | [number, number, number, number]
+  | [number, number, number, number, number];
+
+type _BabelDecodedSourceMap = Readonly<{
+  file?: string,
+  mappings: Array<Array<_BabelDecodedSourceMapSegment>>,
+  names: Array<string>,
+  sourceRoot?: string,
+  sources: Array<string>,
+  sourcesContent?: Array<?string>,
+  version: number,
+}>;
+
 export type BabelSourceLocation = Readonly<{
   start: Readonly<{line: number, column: number}>,
   end: Readonly<{line: number, column: number}>,
@@ -1111,6 +1129,7 @@ declare module '@babel/generator' {
   declare export type GeneratorResult = {
     code: string,
     map: ?_BabelSourceMap,
+    decodedMap: ?_BabelDecodedSourceMap,
     rawMappings: ?Array<BabelSourceMapSegment>,
   };