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import { setupRerender } from 'preact/test-utils';
import {
createEvent,
setupScratch,
teardown
} from '../../../test/_util/helpers';
import React, {
createElement,
Component,
render,
memo,
useState
} from 'preact/compat';
import { li, ol } from '../../../test/_util/dom';
const h = React.createElement;
describe('memo()', () => {
/** @type {HTMLDivElement} */
let scratch;
/** @type {() => void} */
let rerender;
beforeEach(() => {
scratch = setupScratch();
rerender = setupRerender();
});
afterEach(() => {
teardown(scratch);
});
it('should have isReactComponent flag', () => {
// eslint-disable-next-line react/display-name
let App = memo(() => <div>foo</div>);
expect(App.prototype.isReactComponent).to.equal(true);
});
it('should work with function components', () => {
let spy = sinon.spy();
function Foo() {
spy();
return <h1>Hello World</h1>;
}
let Memoized = memo(Foo);
let update;
class App extends Component {
constructor() {
super();
update = () => this.setState({});
}
render() {
return <Memoized />;
}
}
render(<App />, scratch);
expect(spy).to.be.calledOnce;
update();
rerender();
expect(spy).to.be.calledOnce;
});
it('should support adding refs', () => {
let spy = sinon.spy();
let ref = null;
function Foo() {
spy();
return <h1>Hello World</h1>;
}
let Memoized = memo(Foo);
let update;
class App extends Component {
constructor() {
super();
update = () => this.setState({});
}
render() {
return <Memoized ref={ref} />;
}
}
render(<App />, scratch);
expect(spy).to.be.calledOnce;
ref = {};
update();
rerender();
expect(ref.current).not.to.be.undefined;
// TODO: not sure whether this is in-line with react...
expect(spy).to.be.calledTwice;
});
it('should support custom comparer functions', () => {
function Foo() {
return <h1>Hello World</h1>;
}
let spy = sinon.spy(() => true);
let Memoized = memo(Foo, spy);
let update;
class App extends Component {
constructor() {
super();
update = () => this.setState({});
}
render() {
return <Memoized />;
}
}
render(<App />, scratch);
update();
rerender();
expect(spy).to.be.calledOnce;
expect(spy).to.be.calledWith({}, {});
});
it('should rerender when custom comparer returns false', () => {
const spy = sinon.spy();
function Foo() {
spy();
return <h1>Hello World</h1>;
}
const App = memo(Foo, () => false);
render(<App />, scratch);
expect(spy).to.be.calledOnce;
render(<App foo="bar" />, scratch);
expect(spy).to.be.calledTwice;
});
it('should pass props and nextProps to comparer fn', () => {
const spy = sinon.spy(() => false);
function Foo() {
return <div>foo</div>;
}
const props = { foo: true };
const nextProps = { foo: false };
const App = memo(Foo, spy);
render(h(App, props), scratch);
render(h(App, nextProps), scratch);
expect(spy).to.be.calledWith(props, nextProps);
});
it('should nest without errors', () => {
const Foo = () => <div>foo</div>;
const App = memo(memo(Foo));
// eslint-disable-next-line prefer-arrow-callback
expect(function() {
render(<App />, scratch);
}).to.not.throw();
});
it('should pass ref through nested memos', () => {
class Foo extends Component {
render() {
return <h1>Hello World</h1>;
}
}
const App = memo(memo(Foo));
const ref = {};
render(<App ref={ref} />, scratch);
expect(ref.current).not.to.be.undefined;
expect(ref.current).to.be.instanceOf(Foo);
});
it('should not unnecessarily reorder children #2895', () => {
const array = [{ name: 'A' }, { name: 'B' }, { name: 'C' }, { name: 'D' }];
const List = () => {
const [selected, setSelected] = useState('');
return (
<ol>
{array.map(item => (
<ListItem
{...{
isSelected: item.name === selected,
setSelected,
...item
}}
key={item.name}
/>
))}
</ol>
);
};
const ListItem = memo(({ name, isSelected, setSelected }) => {
const handleClick = () => setSelected(name);
return (
<li class={isSelected ? 'selected' : null} onClick={handleClick}>
{name}
</li>
);
});
render(<List />, scratch);
expect(scratch.innerHTML).to.equal(
`<ol><li>A</li><li>B</li><li>C</li><li>D</li></ol>`
);
let listItem = scratch.querySelector('li:nth-child(3)');
listItem.dispatchEvent(createEvent('click'));
rerender();
expect(scratch.innerHTML).to.equal(
`<ol><li>A</li><li>B</li><li class="selected">C</li><li>D</li></ol>`
);
});
});
|
