@applicaster/zapp-react-native-utils/appUtils/focusManager/utils/__tests__/findChild.test.ts

Applicaster Zapp React Native utilities package

import { findChild } from "../index";

describe("findChild", () => {
  const makeNode = (children = []) => ({ children });

  const child = (preferredFocus: boolean) => ({
    component: { props: { preferredFocus } },
  });

  it("returns the child with preferredFocus=true", () => {
    const node = makeNode([child(false), child(true), child(false)]);
    expect(findChild(true, node)).toBe(node.children[1]);
  });

  it("returns the child with preferredFocus=false", () => {
    const node = makeNode([child(false), child(true), child(false)]);
    expect(findChild(false, node)).toBe(node.children[0]);
  });

  it("returns undefined if no child matches preferredFocus", () => {
    const node = makeNode([child(false), child(false)]);
    expect(findChild(true, node)).toBeUndefined();
  });

  it("returns undefined if node has no children", () => {
    const node = makeNode();
    expect(findChild(true, node)).toBeUndefined();
    expect(findChild(false, node)).toBeUndefined();
  });

  it("returns undefined if children is not an array", () => {
    const node = { children: null };
    expect(findChild(true, node)).toBeUndefined();
  });
});