add html folding in gts

src/main/kotlin/com/emberjs/gts/GtsFoldingBuilder.kt

@@ -0,0 +1,64 @@
+package com.emberjs.gts
+
+import com.intellij.lang.ASTNode
+import com.intellij.lang.folding.FoldingBuilderEx
+import com.intellij.lang.folding.FoldingDescriptor
+import com.intellij.lang.javascript.JavaScriptSupportLoader
+import com.intellij.lang.javascript.folding.TypeScriptFoldingBuilder
+import com.intellij.lang.xml.XmlFoldingBuilder
+import com.intellij.openapi.editor.Document
+import com.intellij.openapi.project.DumbAware
+import com.intellij.openapi.util.TextRange
+import com.intellij.psi.PsiElement
+import com.intellij.psi.util.PsiTreeUtil
+import com.intellij.psi.util.elementType
+
+
+internal class GtsFoldingBuilder : FoldingBuilderEx(), DumbAware {
+
+    public override fun buildFoldRegions(
+        root: PsiElement,
+        p1: Document,
+        quick: Boolean
+    ): Array<out FoldingDescriptor?> {
+
+        val registeredRanges = mutableSetOf<TextRange>()
+
+        val descriptors = mutableListOf<FoldingDescriptor>()
+
+        val view = root.containingFile.viewProvider
+        val JS = JavaScriptSupportLoader.ECMA_SCRIPT_6
+        val TS = JavaScriptSupportLoader.TYPESCRIPT
+        val tsView = view.getPsi(TS)
+        val jsView = view.getPsi(JS)
+
+        val tsRegions = TypeScriptFoldingBuilder().buildFoldRegions(tsView ?: jsView, p1, quick)
+        val htmlRegions = XmlFoldingBuilder().buildFoldRegions(root, p1, quick)
+
+        val templates = PsiTreeUtil.collectElements(tsView ?: jsView) { it.elementType == GtsElementTypes.GTS_OUTER_ELEMENT_TYPE }
+
+        registeredRanges.addAll(templates.map { it.textRange })
+
+        for (region in tsRegions) {
+            if (!registeredRanges.contains(region.range)) {
+                descriptors.add(region)
+            }
+        }
+
+        for (region in htmlRegions) {
+            if (registeredRanges.contains(region.range)) {
+                descriptors.add(region)
+            }
+        }
+
+        return descriptors.toTypedArray()
+    }
+
+    public override fun getPlaceholderText(node: ASTNode): String? {
+        return null
+    }
+
+    public override fun isCollapsedByDefault(p0: ASTNode): Boolean {
+        return true
+    }
+}

src/main/resources/META-INF/plugin.xml

@@ -82,6 +82,7 @@
         <lang.ast.factory language="Gts" implementationClass="com.emberjs.gts.GtsAstFactory" />
         <lang.formatter language="Gts" implementationClass="com.emberjs.gts.GtsFormattingModelBuilder" />
         <lang.formatter language="Gjs" implementationClass="com.emberjs.gts.GtsFormattingModelBuilder" />
+        <lang.foldingBuilder language="Gts" implementationClass="com.emberjs.gts.GtsFoldingBuilder" />
         <editorNotificationProvider implementation="com.emberjs.glint.GlintEditorNotificationsProvider"/>
         <editorFactoryListener implementation="com.emberjs.hbs.HbMustacheNameSynchronizer$MyEditorFactoryListener"/>
         <typedHandler implementation="com.emberjs.gts.GtsTypeHandler" order="before xmlSlash"/>