[JS IR BE] Add generating JS AST for more IR elements:

* string concat
* get local value
* set local variable

* block
* composite block

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/IrElementToJsExpressionTransformer.kt

@@ -6,6 +6,7 @@
 package org.jetbrains.kotlin.ir.backend.js.transformers.irToJs
 
 import org.jetbrains.kotlin.ir.backend.js.utils.isPrimary
+import org.jetbrains.kotlin.ir.backend.js.utils.name
 import org.jetbrains.kotlin.ir.backend.js.utils.parameterCount
 import org.jetbrains.kotlin.ir.declarations.IrClass
 import org.jetbrains.kotlin.ir.declarations.IrSimpleFunction
@@ -34,6 +35,27 @@ class IrElementToJsExpressionTransformer : BaseIrElementToJsNodeTransformer<JsEx
         }
     }
 
+    override fun visitStringConcatenation(expression: IrStringConcatenation, data: Nothing?): JsExpression {
+        // TODO revisit
+        return expression.arguments.fold<IrExpression, JsExpression>(JsStringLiteral("")) { jsExpr, irExpr ->
+            JsBinaryOperation(
+                JsBinaryOperator.ADD,
+                jsExpr,
+                irExpr.accept(this, data)
+            )
+        }
+    }
+
+    override fun visitGetValue(expression: IrGetValue, data: Nothing?): JsExpression {
+        return JsNameRef(expression.symbol.name.toJsName())
+    }
+
+    override fun visitSetVariable(expression: IrSetVariable, data: Nothing?): JsExpression {
+        val ref = JsNameRef(expression.symbol.name.toJsName())
+        val value = expression.value.accept(this, data)
+        return JsBinaryOperation(JsBinaryOperator.ASG, ref, value)
+    }
+
     override fun visitCall(expression: IrCall, data: Nothing?): JsExpression {
         // TODO rewrite more accurately, right now it just copy-pasted and adopted from old version
         // TODO support:

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/IrElementToJsStatementTransformer.kt

@@ -14,6 +14,15 @@ class IrElementToJsStatementTransformer : BaseIrElementToJsNodeTransformer<JsSta
         return JsBlock(body.statements.map { it.accept(this, data) })
     }
 
+    override fun visitBlock(expression: IrBlock, data: Nothing?): JsBlock {
+        return JsBlock(expression.statements.map { it.accept(this, data) })
+    }
+
+    override fun visitComposite(expression: IrComposite, data: Nothing?): JsStatement {
+        // TODO introduce JsCompositeBlock?
+        return JsBlock(expression.statements.map { it.accept(this, data) })
+    }
+
     override fun visitExpression(expression: IrExpression, data: Nothing?): JsStatement {
         return JsExpressionStatement(expression.accept(IrElementToJsExpressionTransformer(), data))
     }

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/utils/descriptorBasedUtils.kt

@@ -7,7 +7,10 @@ package org.jetbrains.kotlin.ir.backend.js.utils
 
 import org.jetbrains.kotlin.ir.symbols.IrConstructorSymbol
 import org.jetbrains.kotlin.ir.symbols.IrFunctionSymbol
+import org.jetbrains.kotlin.ir.symbols.IrValueSymbol
 
 val IrFunctionSymbol.parameterCount get() = descriptor.valueParameters.size
 
 val IrConstructorSymbol.isPrimary get() = descriptor.isPrimary
+
+val IrValueSymbol.name get() = descriptor.name