Support function interpolation

Author: kateinoigakukun

Diff for: src/swift/Sources/JavaScriptKit/JSValue.swift

@@ -16,13 +16,26 @@ public class JSObjectRef: Equatable {
     }
 }
 
+public class JSFunctionRef: Equatable {
+    let id: UInt32
+
+    fileprivate init(id: UInt32) {
+        self.id = id
+    }
+
+    public static func == (lhs: JSFunctionRef, rhs: JSFunctionRef) -> Bool {
+        return lhs.id == rhs.id
+    }
+}
+
 public enum JSValue: Equatable {
     case boolean(Bool)
     case string(String)
     case number(Int32)
     case object(JSObjectRef)
     case null
     case undefined
+    case function(JSFunctionRef)
 }
 
 protocol JSValueConvertible {
@@ -66,6 +79,8 @@ extension RawJSValue: JSValueConvertible {
             return .null
         case JavaScriptValueKind_Undefined:
             return .undefined
+        case JavaScriptValueKind_Function:
+            return .function(JSFunctionRef(id: payload1))
         default:
             fatalError("unreachable")
         }
@@ -105,6 +120,10 @@ extension JSValue {
             kind = JavaScriptValueKind_Undefined
             payload1 = 0
             payload2 = 0
+        case let .function(functionRef):
+            kind = JavaScriptValueKind_Function
+            payload1 = functionRef.id
+            payload2 = 0
         }
         let rawValue = RawJSValue(kind: kind, payload1: payload1, payload2: payload2)
         return body(rawValue)

Diff for: src/web/src/index.ts

@@ -107,6 +107,9 @@ export class SwiftRuntime {
                 case JavaScriptValueKind.Undefined: {
                     return undefined
                 }
+                case JavaScriptValueKind.Function: {
+                    return this._heapValues[payload1]
+                }
                 default:
                     throw new Error(`Type kind "${kind}" is not supported`)
             }
@@ -156,6 +159,13 @@ export class SwiftRuntime {
                         payload2: 0,
                     }
                 }
+                case "function": {
+                    return {
+                        kind: JavaScriptValueKind.Function,
+                        payload1: allocValue(value),
+                        payload2: 0,
+                    }
+                }
                 default:
                     throw new Error(`Type "${typeof value}" is not supported yet`)
             }

Diff for: test/JavaScriptKitExec/Sources/JavaScriptKitExec/UnitTestUtils.swift

@@ -21,6 +21,14 @@ func expectObject(_ value: JSValue) throws -> JSObjectRef {
     }
 }
 
+func expectFunction(_ value: JSValue) throws -> JSFunctionRef {
+    switch value {
+    case .function(let ref): return ref
+    default:
+        throw MessageError("Type of \(value) should be \"function\"")
+    }
+}
+
 func expectBoolean(_ value: JSValue) throws -> Bool {
     switch value {
     case .boolean(let bool): return bool

Diff for: test/JavaScriptKitExec/Sources/JavaScriptKitExec/main.swift

@@ -35,6 +35,7 @@ Object_Conversion: do {
     //   "prop_4": [
     //     3, 4, "str_elm_1", 5,
     //   ],
+    //   "prop_5": function () {},
     // }
     // ```
     //
@@ -58,6 +59,10 @@ Object_Conversion: do {
         let actualElement = getJSValue(this: prop_4Array, index: Int32(index))
         try expectEqual(actualElement, expectedElement)
     }
+
+    let prop_5 = getJSValue(this: globalObject1Ref, name: "prop_5")
+    _ = try expectFunction(prop_5)
+
 } catch {
     print(error)
 }

Diff for: test/index.js

@@ -27,6 +27,7 @@ global.globalObject1 = {
   "prop_4": [
     3, 4, "str_elm_1", 5,
   ],
+  "prop_5": function () {},
 }
 
 const startWasiTask = async () => {