From 649c439ec696b2d14ee2819c26f73aaecb74c4f2 Mon Sep 17 00:00:00 2001
From: Bobby Schultz <puppybits@gmail.com>
Date: Sun, 23 Sep 2018 12:40:56 -0700
Subject: [PATCH] fix: bundle of large clojurescript output was choking
 Bable/Metro

---
 re-natal.coffee            |   5 ++
 resources/rn-cli.config.js | 104 +++++++++++++++++++++++++++++++++++++
 2 files changed, 109 insertions(+)
 create mode 100644 resources/rn-cli.config.js

diff --git a/re-natal.coffee b/re-natal.coffee
index 6f0fca8..b2d38af 100644
--- a/re-natal.coffee
+++ b/re-natal.coffee
@@ -338,6 +338,8 @@ copyDevEnvironmentFilesForPlatform = (platform, interfaceName, projNameHyph, pro
   edit mainDevPath, [[projNameHyphRx, projNameHyph], [projNameRx, projName], [platformRx, platform]]
 
 generateConfigNs = (config) ->
+  fs.copySync("#{resources}/rn-cli.config.js", "./rn-cli.config.js")
+
   template = hb.compile(readFile "#{resources}/config.cljs")
   fs.writeFileSync("#{config.envRoots.dev}/env/config.cljs", template(config))
 
@@ -561,6 +563,9 @@ init = (interfaceName, projName, platforms) ->
         start: 'node node_modules/react-native/local-cli/cli.js start'
         'run-ios': 'node node_modules/react-native/local-cli/cli.js run-ios',
         'run-android': 'node node_modules/react-native/local-cli/cli.js run-android',
+        # rn-cli-config.js & Node v8+ exposes GC avoids the GC out of memory errors when Babel compiles large Clojurescript output
+        'bundle-ios': 'lein prod-build && node --expose-gc --max_old_space_size=8192 \'./node_modules/react-native/local-cli/cli.js\' bundle --sourcemap-output main.jsbundle.map --bundle-output ios/main.jsbundle --entry-file index.ios.js --platform ios --assets-dest ios',
+        'bundle-android': 'lein prod-build && node --expose-gc --max_old_space_size=8192 \'./node_modules/react-native/local-cli/cli.js\' bundle --sourcemap-output main.jsbundle.map --bundle-output android/main.jsbundle --entry-file index.android.js --platform android --assets-dest android'
       dependencies:
         'react-native': rnVersion
         '@babel/plugin-external-helpers': '^7.0.0'
diff --git a/resources/rn-cli.config.js b/resources/rn-cli.config.js
new file mode 100644
index 0000000..5b51900
--- /dev/null
+++ b/resources/rn-cli.config.js
@@ -0,0 +1,104 @@
+/*
+  This is a custom React Native/Metro Transformer to fix issues
+  with bundling a large single JS file. It works with RNv0.57.
+
+  Add the command below to package.json or project.clj.
+  node --expose-gc --max_old_space_size=8192 \
+    './node_modules/react-native/local-cli/cli.js' bundle \
+    --sourcemap-output main.jsbundle.map \
+    --bundle-output ios/main.jsbundle \
+    --entry-file release.ios.js \
+    --platform ios \
+    --dev true \
+    --assets-dest ios \
+    --config=./rn-cli.config.js",
+*/
+
+var DEBUG = true;
+var debug = DEBUG ?
+  function(){ console.log.call(this, [].slice.call(arguments)); } :
+  function(){};
+
+// Big files can slow down Metro, so we'll dump GC every 30 seconds to be safe.
+(function scheduleGc() {
+  if (!global.gc) {
+    console.log("Garbage collection is not exposed");
+    return;
+  }
+
+  var timeoutId = setTimeout(function() {
+    global.gc();
+    console.log("Manual gc", process.memoryUsage());
+    scheduleGc();
+  }, 30 * 1000);
+  timeoutId.unref();
+})();
+
+// Custom Metro Transform (validated with React Native v0.57)
+var path = require("path");
+var fs = require("fs");
+var defaultTransformer = require("./node_modules/metro/src/reactNativeTransformer");
+
+function clojurescriptTransformer(code, filename) {
+  console.log("Generating sourcemap for " + filename);
+  var map = fs.readFileSync(filename + ".map", { encoding: "utf8" });
+  var sourceMap = JSON.parse(map);
+
+  var sourcesContent = [];
+  sourceMap.sources.forEach(function(path) {
+    var sourcePath = __dirname + "/" + path;
+    var isDirectory = path.indexOf(".") === -1;
+    if (isDirectory) {
+      debug("ignore");
+      return;
+    }
+
+    try {
+      // try and find the corresponding `.cljs` file first
+      var file = sourcePath.replace(".js", ".cljs");
+      debug(file);
+      sourcesContent.push(fs.readFileSync(file, "utf8"));
+    } catch (e) {
+      // otherwise fallback to whatever is listed as the source
+      debug("sourcePath", path);
+      try {
+        sourcesContent.push(fs.readFileSync(sourcePath, "utf8"));
+      } catch (e) {
+        if (sourcePath.match(/\.js$/) !== null) {
+          console.warn("clojurescript transformer error with file ", sourcePath);
+        }
+      }
+    }
+  });
+  sourceMap.sourcesContent = sourcesContent;
+
+  return {
+    filename: filename,
+    code: code.replace("# sourceMappingURL=", ""),
+    map: sourceMap
+  };
+}
+
+
+var customClojurescriptTransformer = function(data){
+  var isCljsEntryFile = data.filename.match(/index\.*\.js/) !== null;
+  console.log('d', data.filename);
+  if (isCljsEntryFile) {
+    debug("using custom clojurescript transformer");
+    return clojurescriptTransformer(data.src, data.filename);
+  } else {
+    return defaultTransformer.transform(data);
+  }
+}
+
+// @see https://facebook.github.io/metro/docs/en/configuration
+var rnCliConfig = {
+  projectRoot: path.resolve(__dirname),
+  getTransformModulePath: () => require.resolve("./rn-cli.config")
+}
+
+module.exports = {
+  transform: customClojurescriptTransformer,
+  projectRoot: projectRoot,
+  getTransformModulePath: rnCliConfig.getTransformModulePath
+};