fix: remote jQuery is not function thrown when jQuery overwritten in app as non-function (#32682)

* fix: address jquery remote is not a function error

* remove some comments

* add link to issue

* add link to issue in code

* add comments to ignore ts checks

* add changelog entry

* update to ts-expect-error

Author: jennifer-shehane

cli/CHANGELOG.md

@@ -3,6 +3,10 @@
 
 _Released 10/21/2025 (PENDING)_
 
+**Bugfixes:**
+
+- An error is no longer thrown during command execution when the application under test overwrites the `window.$` property with a non-function. Fixes [#1502](https://github.com/cypress-io/cypress/issues/1502). Fixed in [#32682](https://github.com/cypress-io/cypress/pull/32682).
+
 **Misc:**
 
 Browser detection in Cypress now always prefers 64-bit browser installs to 32-bit browser installs. Addressed in [#32656](https://github.com/cypress-io/cypress/pull/32656).

packages/driver/cypress/e2e/dom/jquery.cy.ts

@@ -1,6 +1,7 @@
 describe('src/dom/jquery', () => {
   context('.isJquery', () => {
     it('does not get confused when window contains jquery function', () => {
+      // @ts-expect-error - Intentionally adding jquery property to test conflict detection
       window.jquery = () => {}
 
       expect(Cypress.dom.isJquery(window)).to.be.false
@@ -16,7 +17,7 @@ describe('src/dom/jquery', () => {
 
       cy.get('#dom').then(($el) => {
         expect(Cypress.dom.isJquery($el[0])).to.eql(false)
-        // @ts-ignore
+        // @ts-expect-error
         expect(Cypress.dom.isJquery()).to.eql(false)
       })
     })
@@ -33,4 +34,81 @@ describe('src/dom/jquery', () => {
     cy.visit('fixtures/dom.html')
     cy.noop(cy.$$('#should-not-exist')).scrollTo('250px', '250px')
   })
+
+  // https://github.com/cypress-io/cypress/issues/1502
+  context('jQuery conflicts', () => {
+    it('handles window.$ overridden with non-function value (dynamic)', () => {
+      cy.visit('fixtures/dom.html')
+
+      // Override window.$ with a string value after page load
+      cy.window().then((win) => {
+        // @ts-expect-error - Intentionally overriding jQuery with non-function to test conflict handling
+        win.$ = 'foo'
+      })
+
+      // This should not throw "remoteJQuery is not a function" error
+      cy.get('#dom').then(() => {
+        // Test should pass without errors
+      })
+    })
+
+    it('handles window.$ overridden with object value (dynamic)', () => {
+      cy.visit('fixtures/dom.html')
+
+      // Override window.$ with an object value after page load
+      cy.window().then((win) => {
+        // @ts-expect-error - Intentionally overriding jQuery with non-function to test conflict handling
+        win.$ = { notAFunction: true }
+      })
+
+      // This should not throw "remoteJQuery is not a function" error
+      cy.get('#dom').then(() => {
+        // Test should pass without errors
+      })
+    })
+
+    it('handles window.$ overridden with non-function value (static)', () => {
+      // Test with window.$ pre-set in HTML
+      cy.visit('fixtures/jquery-conflict-test.html')
+
+      // This should not throw "remoteJQuery is not a function" error
+      cy.get('h1').then(() => {
+        // Test should pass without errors
+      })
+    })
+
+    it('reproduces the exact user issue: window.$ = "foo" with h1 element', () => {
+      cy.visit('fixtures/jquery-conflict-test.html')
+
+      // The HTML already has window.$ = 'foo' set
+      // This should not throw "remoteJQuery is not a function" error
+      cy.get('h1').then(() => {
+        // Test should pass without errors - this was failing before the fix
+      })
+    })
+
+    it('assertions work correctly when window.$ is overridden', () => {
+      cy.visit('fixtures/jquery-conflict-test.html')
+
+      // Test that assertions work properly
+      cy.get('h1')
+      .should('contain', 'Hello world')
+      .should('be.visible')
+      .should('have.text', 'Hello world')
+      .then(($el) => {
+        expect($el).to.exist
+        expect($el.text()).to.equal('Hello world')
+      })
+    })
+
+    it('should commands work with jQuery conflicts', () => {
+      cy.visit('fixtures/jquery-conflict-test.html')
+
+      // Test should() with function callback
+      cy.get('h1').should(($el) => {
+        expect($el).to.exist
+        expect($el.text()).to.equal('Hello world')
+      })
+    })
+  })
 })

packages/driver/cypress/fixtures/jquery-conflict-test.html

@@ -0,0 +1,12 @@
+<!DOCTYPE html>
+<html>
+<head>
+    <title>jQuery Conflict Test</title>
+</head>
+<body>
+    <h1>Hello world</h1>
+    <script>
+        window.$ = 'foo'
+    </script>
+</body>
+</html>

packages/driver/src/cy/jquery.ts

@@ -29,6 +29,12 @@ export const create = (state: StateFunc) => ({
     const remoteJQuery = state('jQuery') || state('window').$
 
     if (remoteJQueryisNotSameAsGlobal(remoteJQuery)) {
+      // Check if remoteJQuery is actually a function before calling it
+      // https://github.com/cypress-io/cypress/issues/1502
+      if (typeof remoteJQuery !== 'function') {
+        return
+      }
+
       const remoteSubject = remoteJQuery(subject)
 
       return remoteSubject