style: factor out table length transpilation into common function

YoRyan · YoRyan · commit d1bf66a73f8e · 2022-08-29T01:50:30.000Z
diff --git a/src/transformation/builtins/array.ts b/src/transformation/builtins/array.ts
@@ -30,7 +30,17 @@ export function transformArrayConstructorCall(
     }
 }
 
-const lua50TableLength = lua.createTableIndexExpression(lua.createIdentifier("table"), lua.createStringLiteral("getn"));
+function createTableLengthExpression(context: TransformationContext, expression: lua.Expression, node?: ts.Expression) {
+    if (context.luaTarget === LuaTarget.Lua50) {
+        const tableGetn = lua.createTableIndexExpression(
+            lua.createIdentifier("table"),
+            lua.createStringLiteral("getn")
+        );
+        return lua.createCallExpression(tableGetn, [expression], node);
+    } else {
+        return lua.createUnaryExpression(expression, lua.SyntaxKind.LengthOperator, node);
+    }
+}
 
 /**
  * Optimized single element Array.push
@@ -50,9 +60,7 @@ function transformSingleElementArrayPush(
 
     // #array + 1
     let lengthExpression: lua.Expression = lua.createBinaryExpression(
-        context.luaTarget === LuaTarget.Lua50
-            ? lua.createCallExpression(lua50TableLength, [arrayIdentifier])
-            : lua.createUnaryExpression(arrayIdentifier, lua.SyntaxKind.LengthOperator),
+        createTableLengthExpression(context, arrayIdentifier),
         lua.createNumericLiteral(1),
         lua.SyntaxKind.AdditionOperator
     );
@@ -189,9 +197,7 @@ export function transformArrayProperty(
     switch (node.name.text) {
         case "length":
             const expression = context.transformExpression(node.expression);
-            return context.luaTarget === LuaTarget.Lua50
-                ? lua.createCallExpression(lua50TableLength, [expression], node)
-                : lua.createUnaryExpression(expression, lua.SyntaxKind.LengthOperator, node);
+            return createTableLengthExpression(context, expression, node);
         default:
             return undefined;
     }
