refactor: Added a separate bundle for Json Schema Validator (#454)

Summary:

Since all the code was common JS earlier, json schema validator could be imported directly from source code. Now its no longer possible because its converted to Es module. Created a separate Cjs bundle for json schema validator to serve the same purpose.

Test plan:

Manually tested thoroughly

Author: zashraf1985

packages/optimizely-sdk/CHANGELOG.MD

@@ -13,11 +13,11 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Removed `Promise` polyfill from browser entry point ([417](https://github.com/optimizely/javascript-sdk/pull/417)).
 - Changed functionality of JSON schema validation in all entry points ([442](https://github.com/optimizely/javascript-sdk/pull/442)).
    - Previously, `skipJSONValidation` flag was used by the user to specify whether the JSON object should be validated.
-   - Now, `skipJSONValidation` has been removed entirely from all entry points. Instead, a user will need to import `jsonSchemaValidator` from `@optimizely/optimizely-sdk/lib/utils/json_schema_validator` and pass it to `createInstance` to perform validation as shown below:
+   - Now, `skipJSONValidation` has been removed entirely from all entry points. Instead, a user will need to import `jsonSchemaValidator` from `@optimizely/optimizely-sdk/dist/optimizely.json_schema_validator.min.js` and pass it to `createInstance` to perform validation as shown below:
 
   ```js
   const optimizelySDK = require('@optimizely/optimizely-sdk');
-  const jsonSchemaValidator = require('@optimizely/optimizely-sdk/lib/utils/json_schema_validator');
+  const jsonSchemaValidator = require('@optimizely/optimizely-sdk/dist/optimizely.json_schema_validator.min');
 
   // Require JSON schema validation for the datafile
   var optimizelyClientInstance = optimizely.createInstance({

packages/optimizely-sdk/rollup.config.js

@@ -87,10 +87,27 @@ const umdconfig = {
   ],
 };
 
+// A separate bundle for json schema validator.
+const jsonSchemaValidatorConfig = {
+  plugins: [
+    resolve(),
+    commonjs(),
+  ],
+  external: ['json-schema', '@optimizely/js-sdk-utils'],
+  input: 'lib/utils/json_schema_validator/index.js',
+  output: {
+    exports: 'named',
+    format: 'cjs',
+    file: 'dist/optimizely.json_schema_validator.min.js',
+    plugins: [ terser() ],
+  }
+};
+
 export default [
   BUILD_ALL && getCjsConfigForPlatform('node'),
   BUILD_ALL && getCjsConfigForPlatform('browser'),
   BUILD_ALL && getCjsConfigForPlatform('react_native'),
   BUILD_ALL && esModuleConfig,
+  BUILD_ALL && jsonSchemaValidatorConfig,
   (BUILD_ALL || BUILD_UMD_BUNDLE) && umdconfig,
 ].filter(config => config);