[JS IR BE] Lower kotlin.js.Json external interface methods

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/calls/CallsLowering.kt

@@ -25,7 +25,8 @@ class CallsLowering(val context: JsIrBackendContext) : FileLoweringPass {
         MethodsOfAnyCallsTransformer(context),
         ReflectionCallsTransformer(context),
         EnumIntrinsicsTransformer(context),
-        ExceptionHelperCallsTransformer(context)
+        ExceptionHelperCallsTransformer(context),
+        JsonIntrinsics(context)
     )
 
     override fun lower(irFile: IrFile) {

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/calls/JsonIntrinsics.kt

@@ -0,0 +1,51 @@
+/*
+ * Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.ir.backend.js.lower.calls
+
+import org.jetbrains.kotlin.ir.backend.js.JsIrBackendContext
+import org.jetbrains.kotlin.ir.expressions.IrDynamicOperator
+import org.jetbrains.kotlin.ir.expressions.IrExpression
+import org.jetbrains.kotlin.ir.expressions.IrFunctionAccessExpression
+import org.jetbrains.kotlin.ir.expressions.impl.IrDynamicOperatorExpressionImpl
+import org.jetbrains.kotlin.ir.util.fqNameWhenAvailable
+import org.jetbrains.kotlin.name.FqName
+
+
+class JsonIntrinsics(val context: JsIrBackendContext) : CallsTransformer {
+
+    override fun transformFunctionAccess(call: IrFunctionAccessExpression): IrExpression {
+
+        fun generateMemberAccess(): IrExpression {
+            val obj = call.dispatchReceiver!!
+            val propertyName = call.getValueArgument(0)!!
+            return IrDynamicOperatorExpressionImpl(
+                call.startOffset,
+                call.endOffset,
+                context.irBuiltIns.anyNType,
+                operator = IrDynamicOperator.ARRAY_ACCESS
+            ).also {
+                it.receiver = obj
+                it.arguments.add(propertyName)
+            }
+        }
+
+        when (call.symbol.owner.fqNameWhenAvailable) {
+            FqName("kotlin.js.Json.get") ->
+                return generateMemberAccess()
+
+            FqName("kotlin.js.Json.set") -> {
+                val value = call.getValueArgument(1)!!
+
+                return IrDynamicOperatorExpressionImpl(call.startOffset, call.endOffset, call.type, IrDynamicOperator.EQ).also {
+                    it.receiver = generateMemberAccess()
+                    it.arguments.add(value)
+                }
+
+            }
+        }
+        return call
+    }
+}