feat: make init command standalone (#1167)

package.json

@@ -43,6 +43,7 @@
   "main": "scripts/configure.js",
   "bin": {
     "configure-test-app": "scripts/configure.js",
+    "init": "scripts/init.js",
     "init-test-app": "scripts/init.js",
     "install-windows-test-app": "windows/test-app.js"
   },

scripts/configure.js

@@ -34,6 +34,7 @@ const semver = require("semver");
  * @typedef {{
  *   name: string;
  *   packagePath: string;
+ *   templatePath?: string;
  *   testAppPath: string;
  *   targetVersion: string;
  *   platforms: Platform[];
@@ -407,13 +408,15 @@ const getConfig = (() => {
       typeof configuration === "undefined" ||
       "JEST_WORKER_ID" in process.env // skip caching when testing
     ) {
-      const { name, testAppPath, flatten, init } = params;
+      const { name, templatePath, testAppPath, flatten, init } = params;
       const projectPathFlag = flatten ? " --project-path ." : "";
       const testAppRelPath = projectRelativePath(params);
-      const templateDir = path.relative(
-        process.cwd(),
-        path.dirname(require.resolve("react-native/template/package.json"))
-      );
+      const templateDir =
+        templatePath ||
+        path.relative(
+          process.cwd(),
+          path.dirname(require.resolve("react-native/template/package.json"))
+        );
       configuration = {
         common: {
           files: {

scripts/init.js

@@ -2,10 +2,155 @@
 // @ts-check
 "use strict";
 
-(async () => {
-  const { version: targetVersion } = require("react-native/package.json");
-  const { configure } = require("./configure");
+const { spawnSync } = require("child_process");
+const path = require("path");
+
+/**
+ * @template T
+ * @param {() => T | null} fn
+ * @returns {() => T | null}
+ */
+function memo(fn) {
+  /** @type {T | null} */
+  let result;
+  return () => {
+    if (result === undefined) {
+      result = fn();
+    }
+    return result;
+  };
+}
+
+/**
+ * Invokes `npm`.
+ * @param {...string} args
+ */
+function npm(...args) {
+  const { error, stderr, stdout } = spawnSync("npm", args, {
+    encoding: "utf-8",
+  });
+  if (!stdout) {
+    if (stderr) {
+      console.error(stderr);
+    }
+    throw error;
+  }
+  return stdout.trim();
+}
+
+/**
+ * Invokes `tar xf`.
+ * @param {string} archive
+ */
+function untar(archive) {
+  return spawnSync("tar", ["xf", archive], { cwd: path.dirname(archive) });
+}
+
+/**
+ * Returns the installed `react-native` manifest, if present.
+ * @returns {string | null}
+ */
+const getInstalledReactNativeManifest = memo(() => {
+  try {
+    const options = { paths: [process.cwd()] };
+    return require.resolve("react-native/package.json", options);
+  } catch (_) {
+    return null;
+  }
+});
+
+/**
+ * Returns the installed `react-native` version, if present.
+ * @returns {string | null}
+ */
+const getInstalledVersion = memo(() => {
+  const manifestPath = getInstalledReactNativeManifest();
+  if (manifestPath) {
+    const { version } = require(manifestPath);
+    return version;
+  }
+
+  return null;
+});
+
+/**
+ * Returns the desired `react-native` version.
+ *
+ * Checks the following in order:
+ *
+ *   - Command line flag, e.g. `--version 0.70`
+ *   - Currently installed `react-native` version
+ *   - Latest version from npm
+ *
+ * @returns {string}
+ */
+function getVersion() {
+  const index = process.argv.lastIndexOf("--version");
+  if (index >= 0) {
+    return process.argv[index + 1];
+  }
+
+  const version = getInstalledVersion();
+  if (version) {
+    return version;
+  }
+
+  return npm("view", "react-native", "version");
+}
+
+/**
+ * Returns the React Native version and path to the template.
+ * @returns {Promise<[string] | [string, string]>}
+ */
+function getTemplate() {
+  return new Promise((resolve, reject) => {
+    const version = getVersion();
+    if (getInstalledVersion() === version) {
+      const rnManifest = getInstalledReactNativeManifest();
+      if (rnManifest) {
+        resolve([version, path.join(path.dirname(rnManifest), "template")]);
+        return;
+      }
+    }
+
+    // `npm view` may return an array if there are multiple versions matching
+    // `version`. If there is only one match, the return type is a string.
+    const tarballs = JSON.parse(
+      npm("view", "--json", `react-native@${version}`, "dist.tarball")
+    );
+    const url = Array.isArray(tarballs)
+      ? tarballs[tarballs.length - 1]
+      : tarballs;
+
+    console.log(`Downloading ${path.basename(url)}...`);
+
+    require("https")
+      .get(url, (res) => {
+        const fs = require("fs");
+        const os = require("os");
+
+        const tmpDir = path.join(os.tmpdir(), "react-native-test-app");
+        fs.mkdirSync(tmpDir, { recursive: true });
 
+        const dest = path.join(tmpDir, path.basename(url));
+        const file = fs.createWriteStream(dest);
+        res.pipe(file);
+        file.on("finish", () => {
+          file.close();
+
+          untar(dest);
+
+          const template = path.join(tmpDir, "package", "template");
+          resolve([version, template]);
+        });
+      })
+      .on("error", (err) => {
+        reject(err);
+      });
+  });
+}
+
+async function main() {
   /**
    * @type {{
    *   name?: string;
@@ -17,8 +162,8 @@
     {
       type: "text",
       name: "name",
-      message: "What is the name of your test app?",
-      initial: "TestApp",
+      message: "What is the name of your app?",
+      initial: "Example",
       validate: Boolean,
     },
     {
@@ -43,22 +188,25 @@
   ]);
 
   if (!name || !packagePath || !platforms) {
-    process.exit(1);
+    return 1;
   }
 
-  const path = require("path");
+  const { configure } = require("./configure");
 
-  const result = configure({
+  const [targetVersion, templatePath] = await getTemplate();
+  return configure({
     name,
     packagePath,
+    templatePath,
     testAppPath: path.resolve(__dirname, ".."),
     targetVersion,
     platforms,
     flatten: true,
     force: true,
     init: true,
   });
-  if (result !== 0) {
-    process.exit(result);
-  }
-})();
+}
+
+main().then((result) => {
+  process.exitCode = result;
+});

yarn.lock

@@ -10942,6 +10942,7 @@ fsevents@^2.3.2:
       optional: true
   bin:
     configure-test-app: scripts/configure.js
+    init: scripts/init.js
     init-test-app: scripts/init.js
     install-windows-test-app: windows/test-app.js
   languageName: unknown