arkit/test/react-dom/src/__tests__/ReactIdentity-test.js

Visualises JavaScript, TypeScript and Flow codebases as meaningful and committable architecture diagrams

/**
 * Copyright (c) Facebook, Inc. and its affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 * @emails react-core
 */

'use strict';

let React;
let ReactDOM;
let ReactTestUtils;

describe('ReactIdentity', () => {
  beforeEach(() => {
    jest.resetModules();
    React = require('react');
    ReactDOM = require('react-dom');
    ReactTestUtils = require('react-dom/test-utils');
  });

  it('should allow key property to express identity', () => {
    let node;
    const Component = props => (
      <div ref={c => (node = c)}>
        <div key={props.swap ? 'banana' : 'apple'} />
        <div key={props.swap ? 'apple' : 'banana'} />
      </div>
    );

    const container = document.createElement('div');
    ReactDOM.render(<Component />, container);
    const origChildren = Array.from(node.childNodes);
    ReactDOM.render(<Component swap={true} />, container);
    const newChildren = Array.from(node.childNodes);
    expect(origChildren[0]).toBe(newChildren[1]);
    expect(origChildren[1]).toBe(newChildren[0]);
  });

  it('should use composite identity', () => {
    class Wrapper extends React.Component {
      render() {
        return <a>{this.props.children}</a>;
      }
    }

    const container = document.createElement('div');
    let node1;
    let node2;
    ReactDOM.render(
      <Wrapper key="wrap1">
        <span ref={c => (node1 = c)} />
      </Wrapper>,
      container,
    );
    ReactDOM.render(
      <Wrapper key="wrap2">
        <span ref={c => (node2 = c)} />
      </Wrapper>,
      container,
    );

    expect(node1).not.toBe(node2);
  });

  function renderAComponentWithKeyIntoContainer(key, container) {
    class Wrapper extends React.Component {
      render() {
        return (
          <div>
            <span ref="span" key={key} />
          </div>
        );
      }
    }

    const instance = ReactDOM.render(<Wrapper />, container);
    const span = instance.refs.span;
    expect(span).not.toBe(null);
  }

  it('should allow any character as a key, in a detached parent', () => {
    const detachedContainer = document.createElement('div');
    renderAComponentWithKeyIntoContainer("<'WEIRD/&\\key'>", detachedContainer);
  });

  it('should allow any character as a key, in an attached parent', () => {
    // This test exists to protect against implementation details that
    // incorrectly query escaped IDs using DOM tools like getElementById.
    const attachedContainer = document.createElement('div');
    document.body.appendChild(attachedContainer);

    renderAComponentWithKeyIntoContainer("<'WEIRD/&\\key'>", attachedContainer);

    document.body.removeChild(attachedContainer);
  });

  it('should not allow scripts in keys to execute', () => {
    const h4x0rKey =
      '"><script>window[\'YOUVEBEENH4X0RED\']=true;</script><div id="';

    const attachedContainer = document.createElement('div');
    document.body.appendChild(attachedContainer);

    renderAComponentWithKeyIntoContainer(h4x0rKey, attachedContainer);

    document.body.removeChild(attachedContainer);

    // If we get this far, make sure we haven't executed the code
    expect(window.YOUVEBEENH4X0RED).toBe(undefined);
  });

  it('should let restructured components retain their uniqueness', () => {
    const instance0 = <span />;
    const instance1 = <span />;
    const instance2 = <span />;

    class TestComponent extends React.Component {
      render() {
        return (
          <div>
            {instance2}
            {this.props.children[0]}
            {this.props.children[1]}
          </div>
        );
      }
    }

    class TestContainer extends React.Component {
      render() {
        return (
          <TestComponent>
            {instance0}
            {instance1}
          </TestComponent>
        );
      }
    }

    expect(function() {
      ReactTestUtils.renderIntoDocument(<TestContainer />);
    }).not.toThrow();
  });

  it('should let nested restructures retain their uniqueness', () => {
    const instance0 = <span />;
    const instance1 = <span />;
    const instance2 = <span />;

    class TestComponent extends React.Component {
      render() {
        return (
          <div>
            {instance2}
            {this.props.children[0]}
            {this.props.children[1]}
          </div>
        );
      }
    }

    class TestContainer extends React.Component {
      render() {
        return (
          <div>
            <TestComponent>
              {instance0}
              {instance1}
            </TestComponent>
          </div>
        );
      }
    }

    expect(function() {
      ReactTestUtils.renderIntoDocument(<TestContainer />);
    }).not.toThrow();
  });

  it('should let text nodes retain their uniqueness', () => {
    class TestComponent extends React.Component {
      render() {
        return (
          <div>
            {this.props.children}
            <span />
          </div>
        );
      }
    }

    class TestContainer extends React.Component {
      render() {
        return (
          <TestComponent>
            <div />
            {'second'}
          </TestComponent>
        );
      }
    }

    expect(function() {
      ReactTestUtils.renderIntoDocument(<TestContainer />);
    }).not.toThrow();
  });

  it('should retain key during updates in composite components', () => {
    class TestComponent extends React.Component {
      render() {
        return <div>{this.props.children}</div>;
      }
    }

    class TestContainer extends React.Component {
      state = {swapped: false};

      swap = () => {
        this.setState({swapped: true});
      };

      render() {
        return (
          <TestComponent>
            {this.state.swapped ? this.props.second : this.props.first}
            {this.state.swapped ? this.props.first : this.props.second}
          </TestComponent>
        );
      }
    }

    const instance0 = <span key="A" />;
    const instance1 = <span key="B" />;

    let wrapped = <TestContainer first={instance0} second={instance1} />;

    wrapped = ReactDOM.render(wrapped, document.createElement('div'));
    const div = ReactDOM.findDOMNode(wrapped);

    const beforeA = div.childNodes[0];
    const beforeB = div.childNodes[1];
    wrapped.swap();
    const afterA = div.childNodes[1];
    const afterB = div.childNodes[0];

    expect(beforeA).toBe(afterA);
    expect(beforeB).toBe(afterB);
  });

  it('should not allow implicit and explicit keys to collide', () => {
    const component = (
      <div>
        <span />
        <span key="0" />
      </div>
    );

    expect(function() {
      ReactTestUtils.renderIntoDocument(component);
    }).not.toThrow();
  });
});