fix(core): resolve @posthog/core/surveys on Metro without package exports

.changeset/core-surveys-subpath-old-metro.md

@@ -0,0 +1,6 @@
+---
+'@posthog/core': patch
+'posthog-react-native': patch
+---
+
+Fix `Unable to resolve module @posthog/core/surveys` when bundling posthog-react-native on React Native 0.71–0.78 without Metro package exports. posthog-react-native 4.47.0 and later also pick up the fix by updating `@posthog/core`.

packages/core/package.json

@@ -34,6 +34,7 @@
   },
   "files": [
     "dist",
+    "surveys",
     "src",
     "!src/__tests__"
   ],

packages/core/src/__tests__/subpath-stubs.spec.ts

@@ -0,0 +1,22 @@
+import { readFileSync } from 'node:fs'
+import { join } from 'node:path'
+
+const packageRoot = join(__dirname, '..', '..')
+const readJson = (path: string): any => JSON.parse(readFileSync(join(packageRoot, path), 'utf8'))
+
+// Metro without package exports (React Native < 0.79 by default) resolves `@posthog/core/surveys`
+// as a folder, so the stub must point at the same files as the `./surveys` export.
+describe('subpath stubs', () => {
+  it('surveys/package.json matches the ./surveys export', () => {
+    const exported = readJson('package.json').exports['./surveys']
+    const stub = readJson('surveys/package.json')
+
+    expect(join('surveys', stub.main)).toBe(join(exported.require))
+    expect(join('surveys', stub.module)).toBe(join(exported.import))
+    expect(join('surveys', stub.types)).toBe(join(exported.types))
+  })
+
+  it('ships the surveys stub', () => {
+    expect(readJson('package.json').files).toContain('surveys')
+  })
+})

packages/core/surveys/package.json

@@ -0,0 +1,6 @@
+{
+  "private": true,
+  "main": "../dist/surveys/index.js",
+  "module": "../dist/surveys/index.mjs",
+  "types": "../dist/surveys/index.d.ts"
+}

packages/react-native/test/core-subpath-stubs.spec.ts

@@ -0,0 +1,28 @@
+import { existsSync, readdirSync, readFileSync, statSync } from 'node:fs'
+import { join } from 'node:path'
+
+const srcDir = join(__dirname, '..', 'src')
+const coreDir = join(__dirname, '..', '..', 'core')
+
+const sourceFiles = (dir: string): string[] =>
+  readdirSync(dir).flatMap((name) => {
+    const path = join(dir, name)
+    return statSync(path).isDirectory() ? sourceFiles(path) : /\.(ts|tsx)$/.test(name) ? [path] : []
+  })
+
+// Metro without package exports (React Native < 0.79 by default) can only resolve
+// `@posthog/core/<subpath>` through a real `<subpath>/package.json` in @posthog/core.
+describe('@posthog/core subpath imports', () => {
+  it('each has a resolvable stub in @posthog/core', () => {
+    const subpaths = new Set(
+      sourceFiles(srcDir).flatMap((file) =>
+        [...readFileSync(file, 'utf8').matchAll(/['"]@posthog\/core\/([\w/-]+)['"]/g)].map((match) => match[1])
+      )
+    )
+
+    expect(subpaths.size).toBeGreaterThan(0)
+    for (const subpath of subpaths) {
+      expect(existsSync(join(coreDir, subpath, 'package.json')), `@posthog/core/${subpath}`).toBe(true)
+    }
+  })
+})