fix(amazon-cognito-identity-js): set crypto for Node (#7136)

* Set crypto for node

* add crypto to webpack externals

* add unit tests for crypto

packages/amazon-cognito-identity-js/__tests__/cryptoSecureRandomInt-test.js

@@ -0,0 +1,59 @@
+const crypto = require('crypto');
+
+describe('cryptoSecureRandomInt test', () => {
+	let windowSpy;
+
+	beforeEach(() => {
+		jest.resetModules();
+		windowSpy = jest.spyOn(window, 'window', 'get');
+	});
+
+	afterEach(() => {
+		windowSpy.mockRestore();
+	});
+
+	test('crypto is set for window (browser)', () => {
+		windowSpy.mockImplementation(() => ({
+			crypto: {
+				getRandomValues: () => [12345],
+			},
+		}));
+
+		const cryptoSecureRandomInt = require('../src/utils/cryptoSecureRandomInt')
+			.default;
+		expect(window.crypto).toBeTruthy();
+		expect(cryptoSecureRandomInt()).toBe(12345);
+	});
+
+	test('crypto is set for window (IE 11)', () => {
+		windowSpy.mockImplementation(() => ({
+			crypto: undefined,
+			msCrypto: {
+				getRandomValues: () => [67890],
+			},
+		}));
+
+		const cryptoSecureRandomInt = require('../src/utils/cryptoSecureRandomInt')
+			.default;
+		expect(window.msCrypto).toBeTruthy();
+		expect(cryptoSecureRandomInt()).toBe(67890);
+	});
+
+	test('crypto is set for Node', () => {
+		windowSpy.mockImplementation(() => ({
+			crypto: null,
+		}));
+
+		const randomBytesMock = jest
+			.spyOn(crypto, 'randomBytes')
+			.mockImplementationOnce(() => ({
+				readInt32LE: jest.fn().mockReturnValueOnce(54321),
+			}));
+
+		const cryptoSecureRandomInt = require('../src/utils/cryptoSecureRandomInt')
+			.default;
+		expect(cryptoSecureRandomInt()).toBe(54321);
+
+		randomBytesMock.mockRestore();
+	});
+});

packages/amazon-cognito-identity-js/src/utils/cryptoSecureRandomInt.js

@@ -15,6 +15,13 @@ if (!crypto && typeof global !== 'undefined' && global.crypto) {
 	crypto = global.crypto;
 }
 
+// Native crypto import via require (NodeJS)
+if (!crypto && typeof require === 'function') {
+	try {
+		crypto = require('crypto');
+	} catch (err) {}
+}
+
 /*
  * Cryptographically secure pseudorandom number generator
  * As Math.random() is cryptographically not safe to use

packages/amazon-cognito-identity-js/webpack.config.js

@@ -36,6 +36,9 @@ var config = {
 		devtoolModuleFilenameTemplate: require('../aws-amplify/webpack-utils')
 			.devtoolModuleFilenameTemplate,
 	},
+	externals: {
+		crypto: 'crypto',
+	},
 	plugins: [
 		new webpack.optimize.OccurrenceOrderPlugin(),
 		new webpack.BannerPlugin({ banner, raw: true }),