Render the appropriate fields depending on the postType in templates

Author: SantosGuillamot

packages/editor/src/bindings/post-meta.js

@@ -82,31 +82,65 @@ export default {
 return true;
 },
 getFieldsList( { registry, context } ) {
-const metaFields = registry
-.select( coreDataStore )
-.getEditedEntityRecord(
+let metaFields = {};
+const {
+type,
+is_custom: isCustom,
+slug,
+} = registry.select( editorStore ).getCurrentPost();
+const { getPostTypes, getEntityRecord, getEditedEntityRecord } =
+registry.select( coreDataStore );
+
+// If it is a template, use the default values.
+if ( type === 'wp_template' ) {
+let postType;
+let isGlobalTemplate = false;
+// Get the 'kind' from the start of the slug.
+const [ kind ] = slug.split( '-' );
+if ( isCustom || slug === 'index' ) {
+isGlobalTemplate = true;
+// Use 'post' as the default.
+postType = 'post';
+} else if ( kind === 'page' ) {
+postType = 'page';
+} else if ( kind === 'single' ) {
+const postTypes =
+getPostTypes( { per_page: -1 } )?.map(
+( entity ) => entity.slug
+) || [];
+
+// Infer the post type from the slug.
+const match = slug.match(
+`^single-(${ postTypes.join( '|' ) })(?:-.+)?$`
+);
+postType = match ? match[ 1 ] : 'post';
+}
+
+// TODO: Fields returns undefined on the first click.
+const fields = getEntityRecord(
+'root',
+'postType',
+postType
+)?.meta;
+
+// Populate the `metaFields` object with the default values.
+Object.entries( fields || {} ).forEach( ( [ key, props ] ) => {
+// If the template is global, skip the fields with a subtype.
+if ( isGlobalTemplate && props.subtype ) {
+return;
+}
+metaFields[ key ] = props.default;
+} );
+} else {
+metaFields = getEditedEntityRecord(
 'postType',
 context?.postType,
 context?.postId
 ).meta;
-
-// TODO: Fields returns undefined on the first click.
-const fields = registry
-.select( coreDataStore )
-// TODO: Last item 'post' should not be hardcoded.
-.getEntityRecord( 'root', 'postType', 'post' );
+}
 
 if ( ! metaFields || ! Object.keys( metaFields ).length ) {
-if ( ! fields?.meta ) {
-return null;
-}
-const metaDefaults = {};
-for ( const key in fields.meta ) {
-if ( fields.meta.hasOwnProperty( key ) ) {
-metaDefaults[ key ] = fields.meta[ key ].default;
-}
-}
-return metaDefaults;
+return null;
 }
 
 // Remove footnotes or private keys from the list of fields.