Make line counts reflect all line endings

packages/metro-source-map/src/source-map.js

@@ -277,9 +277,10 @@ function addMapping(generator, mapping, carryOver) {
   }
 }
 
-function countLines(string) {
-  return string.split('\n').length;
-}
+const newline = /\r\n?|\n|\u2028|\u2029/g;
+
+const countLines = (string: string): number =>
+  (string.match(newline) || []).length + 1;
 
 module.exports = {
   BundleBuilder,

packages/metro-transform-worker/src/__tests__/index-test.js

@@ -600,3 +600,18 @@ it('skips minification in Hermes canary transform profile', async () => {
     });"
   `);
 });
+
+it('counts all line endings correctly', async () => {
+  const result = await Transformer.transform(
+    baseConfig,
+    '/root',
+    'local/file.js',
+    'one\rtwo\r\nthree\nfour\u2028five\u2029six',
+    {
+      dev: false,
+      minify: false,
+      type: 'module',
+    },
+  );
+  expect(result.output[0].data.lineCount).toEqual(9);
+});

packages/metro/src/lib/countLines.js

@@ -10,12 +10,9 @@
 
 'use strict';
 
-const nullthrows = require('nullthrows');
+const newline = /\r\n?|\n|\u2028|\u2029/g;
 
-const reLine = /^/gm;
-
-function countLines(s: string): number {
-  return nullthrows(s.match(reLine)).length;
-}
+const countLines = (string: string): number =>
+  (string.match(newline) || []).length + 1;
 
 module.exports = countLines;

packages/metro/src/shared/output/RamBundle/util.js

@@ -20,10 +20,7 @@ import type {
   BasicSourceMap,
 } from 'metro-source-map';
 
-const newline = /\r\n?|\n|\u2028|\u2029/g;
-// fastest implementation
-const countLines = (string: string): number =>
-  (string.match(newline) || []).length + 1;
+import countLines from '../../../lib/countLines';
 
 function lineToLineSourceMap(
   source: string,