feat: optimize referenced objects

src/index.ts

@@ -15,6 +15,7 @@ import { combineStringLiterals } from './visitors/combineStringLiterals';
 import { createConditionalExpression } from './visitors/createConditionalExpression';
 import { removeUnnecessaryCalls } from './visitors/removeUnnecessaryCalls';
 import { createObjectKeyLookups } from './visitors/createObjectKeyLookups';
+import { referencedObjects } from './visitors/referencedObjects';
 
 const visitors = [
   collectCalls,
@@ -28,6 +29,7 @@ const visitors = [
   createConditionalExpression,
   removeUnnecessaryCalls,
   createObjectKeyLookups,
+  referencedObjects,
 ];
 
 export default (): babel.PluginObj<{ opts?: Partial<PluginOptions>; filename: string }> => ({
@@ -43,14 +45,18 @@ export default (): babel.PluginObj<{ opts?: Partial<PluginOptions>; filename: st
 
       const internalState = new Map<string, any>();
 
-      const runVisitors = (expression: babel.NodePath<t.CallExpression>) => {
+      const runVisitors = (
+        expression: babel.NodePath<t.CallExpression>,
+        pushToQueue: (expression: babel.NodePath<t.CallExpression>) => void,
+      ) => {
         for (const visitor of visitors) {
           visitor({
             program: path,
             expression,
             state: internalState,
             options,
             filename: state.filename,
+            pushToQueue,
           });
 
           if (!expression.isCallExpression()) {
@@ -64,7 +70,12 @@ export default (): babel.PluginObj<{ opts?: Partial<PluginOptions>; filename: st
 
         if (isImportMap(item)) {
           for (let y = 0; y < item.expressions.length; y++) {
-            if (runVisitors(item.expressions[y]) === false) {
+            if (
+              runVisitors(item.expressions[y], newExpression => {
+                item.expressions.push(newExpression);
+                item.referenceCount += 1;
+              }) === false
+            ) {
               item.expressions.splice(y, 1);
               item.referenceCount -= 1;
               y -= 1;
@@ -77,7 +88,11 @@ export default (): babel.PluginObj<{ opts?: Partial<PluginOptions>; filename: st
               break;
             }
           }
-        } else if (runVisitors(item) === false) {
+        } else if (
+          runVisitors(item, newExpression => {
+            expressions.push(newExpression);
+          }) === false
+        ) {
           expressions.splice(x, 1);
           x -= 1;
         }

src/types.ts

@@ -8,4 +8,5 @@ export type VisitorFunction = (params: {
   options: PluginOptions;
   state: Map<string, any>;
   filename: string;
+  pushToQueue: (expression: babel.NodePath<t.CallExpression>) => void;
 }) => void;

src/visitors/referencedObjects.ts

@@ -0,0 +1,29 @@
+import * as t from '@babel/types';
+import { VisitorFunction } from '../types';
+
+export const referencedObjects: VisitorFunction = ({ expression, pushToQueue }) => {
+  const args = expression.get('arguments');
+
+  for (const nodePath of args) {
+    if (!nodePath.isIdentifier()) {
+      continue;
+    }
+
+    const binding = nodePath.scope.getBinding(nodePath.node.name);
+    if (!binding) {
+      continue;
+    }
+
+    if (
+      binding.references === 1 &&
+      binding.constant &&
+      binding.path.isVariableDeclarator() &&
+      t.isObjectExpression(binding.path.node.init)
+    ) {
+      const init = binding.path.get('init');
+
+      init.replaceWith(t.callExpression(expression.node.callee, [binding.path.node.init]));
+      pushToQueue(init as babel.NodePath<t.CallExpression>);
+    }
+  }
+};

test/fixtures/referenced-object/code.js

@@ -0,0 +1,11 @@
+// https://github.com/DestinyItemManager/DIM/blob/a441eff6be8cbdd48477baa9ac30d9147153a08e/src/app/inventory/InventoryItem.tsx#L84-L89
+
+const itemStyles = {
+  [styles.searchHidden]: searchHidden,
+  [styles.subclassPathTop]: subclassPath && subclassPath.position === 'top',
+  [styles.subclassPathMiddle]: subclassPath && subclassPath.position === 'middle',
+  [styles.subclassPathBottom]: subclassPath && subclassPath.position === 'bottom',
+};
+
+// https://github.com/DestinyItemManager/DIM/blob/a441eff6be8cbdd48477baa9ac30d9147153a08e/src/app/inventory/InventoryItem.tsx#L102
+clsx('foo', itemStyles);

test/fixtures/referenced-object/output.js

@@ -0,0 +1,10 @@
+const itemStyles = clsx(
+  subclassPath &&
+    {
+      top: styles.subclassPathTop,
+      middle: styles.subclassPathMiddle,
+      bottom: styles.subclassPathBottom,
+    }[subclassPath.position],
+  searchHidden && styles.searchHidden,
+);
+clsx('foo', itemStyles);