From d178e7543ef61172582f849b9be6bf3eaca8bae3 Mon Sep 17 00:00:00 2001
From: Myles Borins <mylesborins@google.com>
Date: Tue, 5 Mar 2019 20:31:06 -0500
Subject: [PATCH] esm: store json modules in CJS cache

---
 lib/internal/modules/esm/translators.js         | 14 ++++++++++++++
 test/es-module/test-esm-json-cache.mjs          | 13 +++++++++++++
 test/fixtures/es-modules/json-cache/another.cjs |  7 +++++++
 test/fixtures/es-modules/json-cache/mod.cjs     |  7 +++++++
 test/fixtures/es-modules/json-cache/test.json   |  5 +++++
 5 files changed, 46 insertions(+)
 create mode 100644 test/es-module/test-esm-json-cache.mjs
 create mode 100644 test/fixtures/es-modules/json-cache/another.cjs
 create mode 100644 test/fixtures/es-modules/json-cache/mod.cjs
 create mode 100644 test/fixtures/es-modules/json-cache/test.json

diff --git a/lib/internal/modules/esm/translators.js b/lib/internal/modules/esm/translators.js
index 8873e84316..5ddddfa941 100644
--- a/lib/internal/modules/esm/translators.js
+++ b/lib/internal/modules/esm/translators.js
@@ -102,11 +102,25 @@ translators.set('json', async (url) => {
   debug(`Translating JSONModule ${url}`);
   debug(`Loading JSONModule ${url}`);
   const pathname = fileURLToPath(url);
+  const modulePath = isWindows ?
+    StringReplace(pathname, winSepRegEx, '\\') : pathname;
+  const module = CJSModule._cache[modulePath];
+  if (module && module.loaded) {
+    const exports = module.exports;
+    return createDynamicModule(['default'], url, (reflect) => {
+      reflect.exports.default.set(exports);
+    });
+  }
   const content = await readFileAsync(pathname, 'utf-8');
   return createDynamicModule(['default'], url, (reflect) => {
     debug(`Parsing JSONModule ${url}`);
     try {
       const exports = JsonParse(stripBOM(content));
+      const module = {
+        exports,
+        loaded: true
+      };
+      CJSModule._cache[modulePath] = module;
       reflect.exports.default.set(exports);
     } catch (err) {
       err.message = pathname + ': ' + err.message;
diff --git a/test/es-module/test-esm-json-cache.mjs b/test/es-module/test-esm-json-cache.mjs
new file mode 100644
index 0000000000..53a5123f09
--- /dev/null
+++ b/test/es-module/test-esm-json-cache.mjs
@@ -0,0 +1,13 @@
+// Flags: --experimental-modules --experimental-json-modules
+/* eslint-disable node-core/required-modules */
+import '../common/index.mjs';
+import {strictEqual} from 'assert';
+
+import mod from '../fixtures/es-modules/json-cache/mod.cjs';
+import another from '../fixtures/es-modules/json-cache/another.cjs';
+import test from '../fixtures/es-modules/json-cache/test.json';
+
+
+strictEqual(mod.one, 1);
+strictEqual(another.one, 'zalgo');
+strictEqual(test.one, 'it comes');
diff --git a/test/fixtures/es-modules/json-cache/another.cjs b/test/fixtures/es-modules/json-cache/another.cjs
new file mode 100644
index 0000000000..8c8e9f1c0f
--- /dev/null
+++ b/test/fixtures/es-modules/json-cache/another.cjs
@@ -0,0 +1,7 @@
+const test = require('./test.json');
+
+module.exports = {
+  ...test
+};
+
+test.one = 'it comes';
diff --git a/test/fixtures/es-modules/json-cache/mod.cjs b/test/fixtures/es-modules/json-cache/mod.cjs
new file mode 100644
index 0000000000..1af7ae6a6f
--- /dev/null
+++ b/test/fixtures/es-modules/json-cache/mod.cjs
@@ -0,0 +1,7 @@
+const test = require('./test.json');
+
+module.exports = {
+  ...test
+}
+
+test.one = 'zalgo';
diff --git a/test/fixtures/es-modules/json-cache/test.json b/test/fixtures/es-modules/json-cache/test.json
new file mode 100644
index 0000000000..120cbb2840
--- /dev/null
+++ b/test/fixtures/es-modules/json-cache/test.json
@@ -0,0 +1,5 @@
+{
+  "one": 1,
+  "two": 2,
+  "three": 3
+}