TypeError: Cannot read properties of undefined (reading 'length') JEST test

Question

I am trying to implement jest tests to my project but I have error while running test. The thing is that I dont really have length method in code that I am trying to test. It looks from like it occurs in styled-components. Is there any way to fix it or maybe I am interpreting it wrong?

test

import React from "react";
import { render, screen } from "@testing-library/react";
import ChatBubblesContainer from "./ChatBubblesContainer";

let chats = [];

const mockUseContext = jest.fn().mockImplementation(() => ({
  chats: [],
}));

React.useContext = mockUseContext;

describe("test", () => {
  test("render", () => {
    render(<ChatBubblesContainer />);
    expect(screen.getByTestId("bubbles-container")).toBeInTheDocument();
  });
});

error

TypeError: Cannot read properties of undefined (reading 'length')

      20 | describe("test", () => {
      21 |   test("render", () => {
    > 22 |     render(<ChatBubblesContainer />);
         |           ^
      23 |     expect(screen.getByTestId("bubbles-container")).toBeInTheDocument();
      24 |   });
      25 | });

      at charCodeAt (node_modules/styled-components/src/utils/hash.js:13:22)
      at e.hash [as generateAndInjectStyles] (node_modules/styled-components/src/models/ComponentStyle.js:80:53)
      at generateAndInjectStyles (node_modules/styled-components/src/models/StyledComponent.js:87:22)
      at node_modules/styled-components/src/models/StyledComponent.js:129:30
      at displayName (node_modules/styled-components/src/models/StyledComponent.js:247:14)
      at renderWithHooks (node_modules/react-dom/cjs/react-dom.development.js:16305:18)

Answer 1

this appears when the jest cannot identify some specific methods from specific methods use this code

jest.mock('PACKAGE NAME' , () => {
  MISSING VARIABLE OR FUNCTION IN ERROR DESCRIPTION : () =>  jest.fn();

})