From 3ef66e17e4aac7a188849273609d6a1ce7a007c9 Mon Sep 17 00:00:00 2001
From: Aaron Jensen <aaronjensen@gmail.com>
Date: Sun, 2 Aug 2015 00:15:52 -0700
Subject: [PATCH] Add freeze

---
 lib/freeze.js  | 32 ++++++++++++++++++++++++++++++
 test/.eslintrc |  5 +++++
 test/freeze.js | 53 ++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 90 insertions(+)
 create mode 100644 lib/freeze.js
 create mode 100644 test/.eslintrc
 create mode 100644 test/freeze.js

diff --git a/lib/freeze.js b/lib/freeze.js
new file mode 100644
index 0000000..e4d8eb4
--- /dev/null
+++ b/lib/freeze.js
@@ -0,0 +1,32 @@
+function isFreezable(obj) {
+  if (Object.isFrozen(obj)) {
+    return false;
+  }
+
+  return Array.isArray(obj) || typeof obj === 'object';
+}
+
+function recur(obj) {
+  Object.freeze(obj);
+
+  Object.keys(obj).forEach((key) => {
+    const value = obj[key];
+    if (isFreezable(value)) {
+      recur(value);
+    }
+  });
+
+  return obj;
+}
+
+export default function freeze(obj) {
+  if (process.env.NODE_ENV === 'production') {
+    return obj;
+  }
+
+  if (isFreezable(obj)) {
+    recur(obj);
+  }
+
+  return obj;
+}
diff --git a/test/.eslintrc b/test/.eslintrc
new file mode 100644
index 0000000..3a2e250
--- /dev/null
+++ b/test/.eslintrc
@@ -0,0 +1,5 @@
+{
+  "rules": {
+    "no-unused-expressions": 0
+  }
+}
diff --git a/test/freeze.js b/test/freeze.js
new file mode 100644
index 0000000..ca4a381
--- /dev/null
+++ b/test/freeze.js
@@ -0,0 +1,53 @@
+import { expect } from 'chai';
+import freeze from '../lib/freeze';
+
+describe('freeze', () => {
+  afterEach(() => {
+    delete process.env.NODE_ENV;
+  });
+
+  it('freezes objects', () => {
+    const obj = {};
+    freeze(obj);
+
+    expect(Object.isFrozen(obj)).to.be.true;
+  });
+
+  it('freezes nested objects', () => {
+    const obj = { foo: { bar: 3 } };
+    freeze(obj);
+
+    expect(Object.isFrozen(obj.foo)).to.be.true;
+  });
+
+  it('freezes nested arrays', () => {
+    const obj = [[0]];
+    freeze(obj);
+
+    expect(Object.isFrozen(obj)).to.be.true;
+    expect(Object.isFrozen(obj[0])).to.be.true;
+  });
+
+  it('ignores functions', () => {
+    const obj = { foo: () => 1 };
+    freeze(obj);
+
+    expect(Object.isFrozen(obj.foo)).to.be.false;
+  });
+
+  it('does not freeze children if the parent is already frozen', () => {
+    const obj = { foo: {} };
+    Object.freeze(obj);
+    freeze(obj);
+
+    expect(Object.isFrozen(obj.foo)).to.be.false;
+  });
+
+  it('does not freeze in production', () => {
+    process.env.NODE_ENV = 'production';
+    const obj = {};
+    freeze(obj);
+
+    expect(Object.isFrozen(obj)).to.be.false;
+  });
+});