fix(config): don't overwrite react-native.config.js if it may be configured

Author: tido64

scripts/configure.mjs

@@ -108,6 +108,20 @@ export function mergeConfig(lhs, rhs) {
   };
 }
 
+/**
+ * Returns whether `react-native.config.js` needs to be updated.
+ * @param {string} packagePath
+ * @returns {boolean}
+ */
+function shouldUpdateReactNativeConfig(packagePath, fs = nodefs) {
+  const configPath = path.join(packagePath, "react-native.config.js");
+  const config = readTextFile(configPath, fs);
+  return (
+    !/["'`]react-native-test-app["'`]/.test(config) ||
+    !config.includes("configureProjects")
+  );
+}
+
 /**
  * Sort the keys in specified object.
  * @param {Record<string, unknown>} obj
@@ -609,15 +623,14 @@ export function updatePackageManifest(
 
 /**
  * Writes all specified files to disk.
- * @param {Configuration["files"]} files
+ * @param {[string, string | FileCopy][]} files
  * @param {string} destination
  * @returns {Promise<void[]>}
  */
 export function writeAllFiles(files, destination, fs = nodefs.promises) {
   const options = { recursive: true, mode: 0o755 };
   return Promise.all(
-    Object.keys(files).map(async (filename) => {
-      const content = files[filename];
+    files.map(async ([filename, content]) => {
       if (!content) {
         return;
       }
@@ -665,8 +678,24 @@ export function configure(params, fs = nodefs) {
   }
 
   const { files, oldFiles } = config;
+  const templateFiles = Object.entries(files).filter(([filename]) => {
+    switch (filename) {
+      case "react-native.config.js": {
+        const needsUpdate = shouldUpdateReactNativeConfig(packagePath);
+        if (!needsUpdate) {
+          warn(
+            `skipped modifying '${filename}' because it may already be configured for 'react-native-test-app'`
+          );
+        }
+        return needsUpdate;
+      }
+
+      default:
+        return true;
+    }
+  });
 
-  writeAllFiles(files, packagePath).then(() => {
+  writeAllFiles(templateFiles, packagePath).then(() => {
     const packageManifest = path.join(packagePath, "package.json");
     if (!fs.existsSync(packageManifest)) {
       // We cannot assume that the app itself is an npm package. Some libraries

test/configure/writeAllFiles.test.ts

@@ -17,11 +17,11 @@ describe("writeAllFiles()", () => {
   it("writes all files to disk", async () => {
     setMockFiles({ "file-on-disk": "0" });
     await writeAllFiles(
-      {
-        file0: { source: "file-on-disk" },
-        file1: "1",
-        file2: "2",
-      },
+      [
+        ["file0", { source: "file-on-disk" }],
+        ["file1", "1"],
+        ["file2", "2"],
+      ],
       "test"
     );
 
@@ -32,11 +32,11 @@ describe("writeAllFiles()", () => {
 
   it("ignores files with no content", async () => {
     await writeAllFiles(
-      {
-        file1: "1",
-        file2: "2",
-        file3: "",
-      },
+      [
+        ["file1", "1"],
+        ["file2", "2"],
+        ["file3", ""],
+      ],
       "."
     );
 
@@ -48,25 +48,23 @@ describe("writeAllFiles()", () => {
   it("rethrows write exceptions", async () => {
     await rejects(
       writeAllFiles(
-        {
-          file0: {
-            // This entry will throw an exception
-            source: "Bad Arnold movies.txt",
-          },
-          file1: "1",
-          file2: "2",
-        },
+        [
+          // This entry will throw an exception
+          ["file0", { source: "Bad Arnold movies.txt" }],
+          ["file1", "1"],
+          ["file2", "2"],
+        ],
         "."
       )
     );
 
     await rejects(
       writeAllFiles(
-        {
-          file1: "1",
-          file2: "2",
-          "": "3", // This entry will throw an exception
-        },
+        [
+          ["file1", "1"],
+          ["file2", "2"],
+          ["", "3"], // This entry will throw an exception
+        ],
         "."
       )
     );