From b75ea8aee998aa3629bceba125628025f6107a6e Mon Sep 17 00:00:00 2001
From: Dhruv Sringari <dhruv@smartpass.app>
Date: Sat, 15 Feb 2025 11:34:53 -0500
Subject: [PATCH] Fix bug with variable composition

---
 source/rules/prefer-composition.ts | 27 +++++++++++++++++++++++----
 tests/rules/prefer-composition.ts  | 10 +++++-----
 2 files changed, 28 insertions(+), 9 deletions(-)

diff --git a/source/rules/prefer-composition.ts b/source/rules/prefer-composition.ts
index 90a2962..2f72285 100644
--- a/source/rules/prefer-composition.ts
+++ b/source/rules/prefer-composition.ts
@@ -12,7 +12,7 @@ import {
   isCallExpression,
   isIdentifier,
   isMemberExpression,
-  isVariableDeclarator,
+  isVariableDeclarator
 } from "eslint-etc";
 import { ruleCreator } from "../utils";
 
@@ -141,6 +141,18 @@ const rule = ruleCreator({
       return entry;
     }
 
+    function getArgumentName(callExpression: es.CallExpression) {
+      const { arguments: args } = callExpression;
+      if (args.length === 0) {
+        return undefined;
+      }
+      const [arg] = args;
+      if (isIdentifier(arg)) {
+        return arg.name;
+      }
+      return undefined;
+    }
+
     function getMethodCalleeName(callExpression: es.CallExpression) {
       const { callee } = callExpression;
       if (isMemberExpression(callee)) {
@@ -227,7 +239,7 @@ const rule = ruleCreator({
       const { name } = identifier;
       const { addCallExpressions, subscriptions } = entry;
       const addCallExpression = addCallExpressions.find(
-        (callExpression) => getMethodCalleeName(callExpression) === name
+        (callExpression) => getArgumentName(callExpression) === name
       );
       if (!addCallExpression) {
         return false;
@@ -236,8 +248,15 @@ const rule = ruleCreator({
       if (!object || !couldBeSubscription(object)) {
         return false;
       }
-      subscriptions.add(name);
-      return true;
+      if (isMemberExpression(object) && isIdentifier(object.property)) {
+        subscriptions.add(object.property.name);
+        return true;
+      }
+      if (isIdentifier(object)) {
+        subscriptions.add(object.name);
+        return true;
+      }
+      return false;
     }
 
     return {
diff --git a/tests/rules/prefer-composition.ts b/tests/rules/prefer-composition.ts
index 7084a8e..f3da21c 100644
--- a/tests/rules/prefer-composition.ts
+++ b/tests/rules/prefer-composition.ts
@@ -5,8 +5,8 @@
 
 import { stripIndent } from "common-tags";
 import { fromFixture } from "eslint-etc";
-import rule = require("../../source/rules/prefer-composition");
 import { ruleTester } from "../utils";
+import rule = require("../../source/rules/prefer-composition");
 
 ruleTester({ types: true }).run("prefer-composition", rule, {
   valid: [
@@ -46,10 +46,10 @@ ruleTester({ types: true }).run("prefer-composition", rule, {
           value: string;
           private subscription = new Subscription();
           ngOnInit() {
-            let subscription = of("foo").subscribe(value => this.value = value);
-            this.subscription.add(subscription);1
-            subscription = of("bar").subscribe(value => this.value = value);
-            this.subscription.add(subscription);
+            let foo = of("foo").subscribe(value => this.value = value);
+            this.subscription.add(foo);
+            foo = of("bar").subscribe(value => this.value = value);
+            this.subscription.add(foo);
           }
           ngOnDestroy() {
             this.subscription.unsubscribe();