Add a nullLiteralTypeAnnotation: string property into the Parser object (#37387)

Summary:
Part of #34872
> [Codegen 110] Add a nullLiteralTypeAnnotation: string property into the Parser object and implement it in the FlowParser (returning
NullLiteralTypeAnnotation) and in the TypeScriptParser(returning TSNullKeyword). Replace them in the [parsers/flow/components/events.js](https://github.com/facebook/react-native/blob/e133100721939108b0f28dfa9f60ac627c804018/packages/react-native-codegen/src/parsers/flow/components/events.js#L137-L138) and [parsers/typescript/components/events.js](https://github.com/facebook/react-native/blob/e133100721939108b0f28dfa9f60ac627c804018/packages/react-native-codegen/src/parsers/typescript/components/events.js#L157).

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## Changelog:

[Internal][Added]: Add nullLiteralTypeAnnotation property in Parser object

Pull Request resolved: #37387

Test Plan: `yarn test react-native-codegen`

Reviewed By: dmytrorykun

Differential Revision: D45779075

Pulled By: cipolleschi

fbshipit-source-id: 4ebcf8e1039d7e9188fdfe811fae1720fcba1994

Author: kyawthura-gg

packages/react-native-codegen/src/parsers/flow/components/events.js

@@ -223,7 +223,7 @@ function findEventArgumentsAndType(
         : null;
     if (
       typeAnnotation.typeParameters.params[0].type ===
-      'NullLiteralTypeAnnotation'
+      parser.nullLiteralTypeAnnotation
     ) {
       return {
         argumentProps: [],

packages/react-native-codegen/src/parsers/flow/parser.js

@@ -66,6 +66,8 @@ class FlowParser implements Parser {
   enumDeclaration: string = 'EnumDeclaration';
   interfaceDelcaration: string = 'InterfaceDeclaration';
 
+  nullLiteralTypeAnnotation: string = 'NullLiteralTypeAnnotation';
+
   isProperty(property: $FlowFixMe): boolean {
     return property.type === 'ObjectTypeProperty';
   }

packages/react-native-codegen/src/parsers/parser.js

@@ -98,6 +98,11 @@ export interface Parser {
    */
   interfaceDelcaration: string;
 
+  /**
+   * This is the NullLiteralTypeAnnotation value
+   */
+  nullLiteralTypeAnnotation: string;
+
   /**
    * Given a declaration, it returns true if it is a property
    */

packages/react-native-codegen/src/parsers/parserMock.js

@@ -64,6 +64,8 @@ export class MockedParser implements Parser {
   enumDeclaration: string = 'EnumDeclaration';
   interfaceDelcaration: string = 'InterfaceDelcaration';
 
+  nullLiteralTypeAnnotation: string = 'NullLiteralTypeAnnotation';
+
   isProperty(property: $FlowFixMe): boolean {
     return property.type === 'ObjectTypeProperty';
   }

packages/react-native-codegen/src/parsers/typescript/components/events.js

@@ -237,7 +237,7 @@ function findEventArgumentsAndType(
         : null;
 
     switch (typeAnnotation.typeParameters.params[0].type) {
-      case 'TSNullKeyword':
+      case parser.nullLiteralTypeAnnotation:
       case 'TSUndefinedKeyword':
         return {
           argumentProps: [],

packages/react-native-codegen/src/parsers/typescript/parser.js

@@ -64,6 +64,8 @@ class TypeScriptParser implements Parser {
   enumDeclaration: string = 'TSEnumDeclaration';
   interfaceDelcaration: string = 'TSInterfaceDeclaration';
 
+  nullLiteralTypeAnnotation: string = 'TSNullKeyword';
+
   isProperty(property: $FlowFixMe): boolean {
     return property.type === 'TSPropertySignature';
   }