merge getExtendsProps & getProps fns - Flow (#36891)

Summary:
[Codegen 102] This PR is subtask of umbrella #34872. It extracts the code to compute the `extendsProps` and the props properties in Flow in a `getProps() -> {extendsProps, props}` function into the same `index.js` file. This will help unifying the `buildComponentSchema` functions between Flow and TS so we can factor it out in a later step.

## Changelog:

[INTERNAL][CHANGED] - merge `getExtendsProps` & `getProps` fns into `getProps` fn - Flow.

Pull Request resolved: #36891

Test Plan: - `yarn flow && yarn test react-native-codegen`  --> *should be green.*

Reviewed By: rshest

Differential Revision: D45044653

Pulled By: cipolleschi

fbshipit-source-id: 9fcdaef60dfbc3332d880b19c6e575d948d21986

Author: Pranav-yadav

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

@@ -14,7 +14,6 @@ import type {ComponentSchemaBuilderConfig} from '../../schema.js';
 
 const {getCommands} = require('./commands');
 const {getEvents} = require('./events');
-const {getExtendsProps, removeKnownExtends} = require('./extends');
 const {getProps} = require('./props');
 const {getProperties} = require('./componentsUtils.js');
 const {throwIfMoreThanOneCodegenNativecommands} = require('../../error-utils');
@@ -126,14 +125,10 @@ function buildComponentSchema(
   const types = parser.getTypes(ast);
 
   const propProperties = getProperties(propsTypeName, types);
-
   const commandProperties = getCommandProperties(ast, parser);
+  const {extendsProps, props} = getProps(propProperties, types);
 
-  const extendsProps = getExtendsProps(propProperties, types);
   const options = getOptions(optionsExpression);
-
-  const nonExtendsProps = removeKnownExtends(propProperties, types);
-  const props = getProps(nonExtendsProps, types);
   const events = getEvents(propProperties, types);
   const commands = getCommands(commandProperties, types);
 

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

@@ -10,18 +10,27 @@
 
 'use strict';
 
+import type {
+  ExtendsPropsShape,
+  NamedShape,
+  PropTypeAnnotation,
+} from '../../../CodegenSchema.js';
+import type {TypeDeclarationMap} from '../../utils';
+
 const {
   flattenProperties,
   getSchemaInfo,
   getTypeAnnotation,
 } = require('./componentsUtils.js');
 
-import type {NamedShape, PropTypeAnnotation} from '../../../CodegenSchema.js';
-import type {TypeDeclarationMap} from '../../utils';
-
 // $FlowFixMe[unclear-type] there's no flowtype for ASTs
 type PropAST = Object;
 
+type ExtendsForProp = null | {
+  type: 'ReactNativeBuiltInType',
+  knownTypeName: 'ReactNativeCoreViewProps',
+};
+
 function buildPropSchema(
   property: PropAST,
   types: TypeDeclarationMap,
@@ -46,13 +55,72 @@ function buildPropSchema(
   };
 }
 
+function extendsForProp(
+  prop: PropAST,
+  types: TypeDeclarationMap,
+): ExtendsForProp {
+  if (!prop.argument) {
+    console.log('null', prop);
+  }
+  const name = prop.argument.id.name;
+
+  if (types[name] != null) {
+    // This type is locally defined in the file
+    return null;
+  }
+
+  switch (name) {
+    case 'ViewProps':
+      return {
+        type: 'ReactNativeBuiltInType',
+        knownTypeName: 'ReactNativeCoreViewProps',
+      };
+    default: {
+      throw new Error(`Unable to handle prop spread: ${name}`);
+    }
+  }
+}
+
+function removeKnownExtends(
+  typeDefinition: $ReadOnlyArray<PropAST>,
+  types: TypeDeclarationMap,
+): $ReadOnlyArray<PropAST> {
+  return typeDefinition.filter(
+    prop =>
+      prop.type !== 'ObjectTypeSpreadProperty' ||
+      extendsForProp(prop, types) === null,
+  );
+}
+
+function getExtendsProps(
+  typeDefinition: $ReadOnlyArray<PropAST>,
+  types: TypeDeclarationMap,
+): $ReadOnlyArray<ExtendsPropsShape> {
+  return typeDefinition
+    .filter(prop => prop.type === 'ObjectTypeSpreadProperty')
+    .map(prop => extendsForProp(prop, types))
+    .filter(Boolean);
+}
+/**
+ * Extracts the `props` and `extendsProps` (props with `extends` syntax)
+ * from a type definition AST.
+ */
 function getProps(
   typeDefinition: $ReadOnlyArray<PropAST>,
   types: TypeDeclarationMap,
-): $ReadOnlyArray<NamedShape<PropTypeAnnotation>> {
-  return flattenProperties(typeDefinition, types)
+): {
+  props: $ReadOnlyArray<NamedShape<PropTypeAnnotation>>,
+  extendsProps: $ReadOnlyArray<ExtendsPropsShape>,
+} {
+  const nonExtendsProps = removeKnownExtends(typeDefinition, types);
+  const props = flattenProperties(nonExtendsProps, types)
     .map(property => buildPropSchema(property, types))
     .filter(Boolean);
+
+  return {
+    props,
+    extendsProps: getExtendsProps(typeDefinition, types),
+  };
 }
 
 module.exports = {