init

.eslintrc.js

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+module.exports = {
+  env: {
+    browser: true,
+    es6: true,
+    node: true,
+  },
+  extends: [
+    'eslint:recommended',
+    'plugin:@typescript-eslint/eslint-recommended',
+    'plugin:@typescript-eslint/recommended',
+  ],
+  globals: {
+    Atomics: 'readonly',
+    SharedArrayBuffer: 'readonly',
+  },
+  parser: '@typescript-eslint/parser',
+  parserOptions: {
+    ecmaVersion: 2018,
+    sourceType: 'module',
+  },
+  plugins: ['@typescript-eslint'],
+  rules: {},
+};

.gitignore

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+build/
+
+
+# Created by https://www.toptal.com/developers/gitignore/api/node,macos
+# Edit at https://www.toptal.com/developers/gitignore?templates=node,macos
+
+### macOS ###
+# General
+.DS_Store
+.AppleDouble
+.LSOverride
+
+# Icon must end with two \r
+Icon
+
+
+# Thumbnails
+._*
+
+# Files that might appear in the root of a volume
+.DocumentRevisions-V100
+.fseventsd
+.Spotlight-V100
+.TemporaryItems
+.Trashes
+.VolumeIcon.icns
+.com.apple.timemachine.donotpresent
+
+# Directories potentially created on remote AFP share
+.AppleDB
+.AppleDesktop
+Network Trash Folder
+Temporary Items
+.apdisk
+
+### Node ###
+# Logs
+logs
+*.log
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+lerna-debug.log*
+
+# Diagnostic reports (https://nodejs.org/api/report.html)
+report.[0-9]*.[0-9]*.[0-9]*.[0-9]*.json
+
+# Runtime data
+pids
+*.pid
+*.seed
+*.pid.lock
+
+# Directory for instrumented libs generated by jscoverage/JSCover
+lib-cov
+
+# Coverage directory used by tools like istanbul
+coverage
+*.lcov
+
+# nyc test coverage
+.nyc_output
+
+# Grunt intermediate storage (https://gruntjs.com/creating-plugins#storing-task-files)
+.grunt
+
+# Bower dependency directory (https://bower.io/)
+bower_components
+
+# node-waf configuration
+.lock-wscript
+
+# Compiled binary addons (https://nodejs.org/api/addons.html)
+build/Release
+
+# Dependency directories
+node_modules/
+jspm_packages/
+
+# TypeScript v1 declaration files
+typings/
+
+# TypeScript cache
+*.tsbuildinfo
+
+# Optional npm cache directory
+.npm
+
+# Optional eslint cache
+.eslintcache
+
+# Optional stylelint cache
+.stylelintcache
+
+# Microbundle cache
+.rpt2_cache/
+.rts2_cache_cjs/
+.rts2_cache_es/
+.rts2_cache_umd/
+
+# Optional REPL history
+.node_repl_history
+
+# Output of 'npm pack'
+*.tgz
+
+# Yarn Integrity file
+.yarn-integrity
+
+# dotenv environment variables file
+.env
+.env.test
+.env*.local
+
+# parcel-bundler cache (https://parceljs.org/)
+.cache
+.parcel-cache
+
+# Next.js build output
+.next
+
+# Nuxt.js build / generate output
+.nuxt
+lib
+
+# Storybook build outputs
+.out
+.storybook-out
+storybook-static
+
+# rollup.js default build output
+lib/
+
+# Gatsby files
+.cache/
+# Comment in the public line in if your project uses Gatsby and not Next.js
+# https://nextjs.org/blog/next-9-1#public-directory-support
+# public
+
+# vuepress build output
+.vuepress/dist
+
+# Serverless directories
+.serverless/
+
+# FuseBox cache
+.fusebox/
+
+# DynamoDB Local files
+.dynamodb/
+
+# TernJS port file
+.tern-port
+
+# Stores VSCode versions used for testing VSCode extensions
+.vscode-test
+
+# Temporary folders
+tmp/
+temp/
+
+# End of https://www.toptal.com/developers/gitignore/api/node,macos

README.MD

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+# Amazon SNS Message Validator for Node.js
+
+The **Amazon SNS Message Validator for Node.js** library allows you to validate
+that incoming HTTP(S) POST messages are valid Amazon SNS notifications. This
+library is standalone and does not depend on the AWS SDK for JavaScript.
+
+## Installation
+
+The npm module's name is [`aws-sns-validator`](https://www.npmjs.com/package/aws-sns-validator). Install with npm or yarn:
+
+```
+npm i aws-sns-validator
+```
+
+or
+
+```
+yarn add aws-sns-validator
+```
+
+## Basic Usage
+
+To validate a message, you can instantiate a `MessageValidator` object and pass
+an SNS message. The message should be
+the result of calling `JSON.parse` on the body of the HTTP(S) message sent by
+SNS to your endpoint.
+
+The message validator checks the `SigningCertURL`, `SignatureVersion`, and
+`Signature` to make sure they are valid and consistent with the message data.
+
+```javascript
+const  MessageValidator = require('aws-sns-validator');
+const validator = new MessageValidator();
+try {
+    await validator.validate(message);
+     // message has been validated and its signature checked.
+} catch (error) {
+     // Your message could not be validated.
+}
+```
+
+## Notes
+
+The SNS Message Validator relies on the Node crypto module and is only designed
+to work on a server, not in a browser. The validation performed is only
+necessary when subscribing HTTP(S)

__test__/index.test.ts

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+/* eslint-disable @typescript-eslint/no-explicit-any */
+import { MessageValidator } from '../src/index';
+import chai from 'chai';
+const expect = chai.expect;
+
+describe('test validate', () => {
+  it('should throw 404', async () => {
+    const validator = new MessageValidator();
+    const message = {
+      Type: 'Notification',
+      MessageId: '4c807a89-9ef9-543b-bfab-2f4ed41e91b4',
+      TopicArn:
+        'arn:aws:sns:us-east-1:853553028582:marbot-dev-alert-Topic-8CT7ZJRNSA5Y',
+      Subject:
+        'INSUFFICIENT_DATA: "insufficient test" in US East (N. Virginia)',
+      Message:
+        '{"AlarmName":"insufficient test","AlarmDescription":null,"AWSAccountId":"853553028582","NewStateValue":"INSUFFICIENT_DATA","NewStateReason":"tets","StateChangeTime":"2019-08-09T10:19:19.614+0000","Region":"US East (N. Virginia)","OldStateValue":"OK","Trigger":{"MetricName":"CallCount2","Namespace":"AWS/Usage","StatisticType":"Statistic","Statistic":"AVERAGE","Unit":null,"Dimensions":[{"value":"API","name":"Type"},{"value":"PutMetricData","name":"Resource"},{"value":"CloudWatch","name":"Service"},{"value":"None","name":"Class"}],"Period":300,"EvaluationPeriods":1,"ComparisonOperator":"GreaterThanThreshold","Threshold":1.0,"TreatMissingData":"- TreatMissingData:                    missing","EvaluateLowSampleCountPercentile":""}}',
+      Timestamp: '2019-08-09T10:19:19.644Z',
+      SignatureVersion: '1',
+      Signature:
+        'gnCKAUYX6YlBW3dkOmrSFvdB6r82Q2He+7uZV9072sdCP0DSaR46ka/4ymSdDfqilqxjJ9hajd9l7j8ZsL98vYdUbut/1IJ2hsuALF9nd/HwNLPPWvKXaK/Y3Hp57izOpeBAkuR6koitSbXX50lEj7FraaMVQfpexm01z7IUcx4vCCvZBTdQLbkWw+TYWkWNsMrqarW39zy474SmTBCSZlz1eoV6tCwYk2Z2G2awiXpnfsQRRZvHn4ot176oY+ADAFJ0sIa44effQXq+tAWE6/Z3M5rjtfg6OULDM+NGEmnVZL3xyWK8bIzB48ZclQo3ZsvLPGmCNQLlFpaP/3fGGg==',
+      SigningCertURL:
+        'https://sns.us-east-1.amazonaws.com/SimpleNotificationService-6aad65c2f9911b05cd53efda11f913f9.pem',
+      UnsubscribeURL:
+        'https://sns.us-east-1.amazonaws.com/?Action=Unsubscribe&SubscriptionArn=arn:aws:sns:us-east-1:853553028582:marbot-dev-alert-Topic-8CT7ZJRNSA5Y:86a160f0-c3c5-4ae1-ae50-2903eede0af1',
+    };
+    try {
+      await validator.validate(message);
+    } catch (error: any) {
+      expect(error.message).to.equal('expected 200 status code, received: 404');
+    }
+  });
+});

babel.config.js

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+// babel.config.js
+module.exports = {
+  presets: [
+    ['@babel/preset-env', { targets: { node: 'current' } }],
+    '@babel/preset-typescript',
+  ],
+};