From 2bf02785d9aef8b7b265d41cd45e2519a7e04bb4 Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Mon, 21 Sep 2026 20:57:36 +0100
Subject: Support Option in typescript-types

---
 .../output/generators/typescript/TypescriptGenerator.java     | 11 +++++++++++
 .../compiler/output/lang/typescript/TypescriptTypes.java      |  2 ++
 2 files changed, 13 insertions(+)

(limited to 'src/main/java')

diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/output/generators/typescript/TypescriptGenerator.java b/src/main/java/org/zwobble/hobgoblin/compiler/output/generators/typescript/TypescriptGenerator.java
index 25435c5..44bad46 100644
--- a/src/main/java/org/zwobble/hobgoblin/compiler/output/generators/typescript/TypescriptGenerator.java
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/output/generators/typescript/TypescriptGenerator.java
@@ -1,6 +1,7 @@
 package org.zwobble.hobgoblin.compiler.output.generators.typescript;
 
 import org.zwobble.hobgoblin.compiler.builtins.NativeTypes;
+import org.zwobble.hobgoblin.compiler.output.lang.typescript.TypescriptTypes;
 import org.zwobble.hobgoblin.compiler.output.lang.typescript.TypescriptWriter;
 import org.zwobble.hobgoblin.compiler.output.lang.typescript.ast.*;
 import org.zwobble.hobgoblin.compiler.typechecker.TypesInfo;
@@ -11,6 +12,7 @@ import java.io.File;
 import java.io.IOException;
 import java.nio.file.Path;
 import java.util.LinkedHashSet;
+import java.util.List;
 import java.util.SequencedSet;
 import java.util.stream.Collectors;
 
@@ -81,6 +83,15 @@ public class TypescriptGenerator {
     public TypescriptExpression generateTypeExpression(Type value, Context context) {
         return switch (collapseType(value)) {
             case ConstructedType constructedType -> {
+                if (constructedType.constructor().equals(NativeTypes.OPTION)) {
+                    // TODO: How to deal with nested options? Forbid them in
+                    // hobgoblin?
+                    yield new TypescriptTypeUnion(List.of(
+                        generateTypeExpression(constructedType.args().getFirst(), context),
+                        TypescriptTypes.NULL
+                    ));
+                }
+
                 yield new TypescriptConstructedType(
                     generateTypeExpression(constructedType.constructor().genericType(), context),
                     constructedType.args().stream()
diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/typescript/TypescriptTypes.java b/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/typescript/TypescriptTypes.java
index 22f24a3..e6fa609 100644
--- a/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/typescript/TypescriptTypes.java
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/typescript/TypescriptTypes.java
@@ -1,5 +1,6 @@
 package org.zwobble.hobgoblin.compiler.output.lang.typescript;
 
+import org.zwobble.hobgoblin.compiler.output.lang.typescript.ast.TypescriptExpression;
 import org.zwobble.hobgoblin.compiler.output.lang.typescript.ast.TypescriptIdentifier;
 import org.zwobble.hobgoblin.compiler.output.lang.typescript.ast.TypescriptRef;
 
@@ -7,6 +8,7 @@ public class TypescriptTypes {
     private TypescriptTypes() {
     }
 
+    public static final TypescriptExpression NULL = new TypescriptRef(TypescriptIdentifier.of("null"));
     public static final TypescriptRef NUMBER = new TypescriptRef(TypescriptIdentifier.of("number"));
     public static final TypescriptRef READONLY_ARRAY = new TypescriptRef(TypescriptIdentifier.of("ReadonlyArray"));
     public static final TypescriptRef SYMBOL = new TypescriptRef(TypescriptIdentifier.of("Symbol"));
-- 
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