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How to use getSnapshotBeforeUpdate method in storybook-root

Best JavaScript code snippet using storybook-root

getSnapshotBeforeUpdate.test.js

...7import { mount } from 'enzyme'; // 348 K8import sinon from 'sinon';9import '../../../enzyme-setup'10describe('Testing out the getSnapshotBeforeUpdate', () => {11  context('getSnapshotBeforeUpdate()', () => {12   it('testing how getSnapshotBeforeUpdate() gets called', () => {13      class EmptyShapshotMethod extends React.Component {14        constructor(props){15          super(props);16          this.state = {17            username: "Edward"18          }19        }20        getSnapshotBeforeUpdate() {21          return [] || null;22        }23        componentDidUpdate(prevProps, prevState, snapshot){24        }25        render(){26          return <div></div>;27        }28      }29      /*30      Note: 31        1) getSnapshot must either return [] || null32        2) You will need to use getSnapshotBeforeUpdate in conjunction componentDidUpdate33        Flagged Warnings below, if the above criteria are not met => 34        Warning: EmptyShapshotMethod.getSnapshotBeforeUpdate(): A snapshot value (or null) must be returned. You have returned undefined.35        Warning: EmptyShapshotMethod: getSnapshotBeforeUpdate() should be used with 36        componentDidUpdate(). This component defines getSnapshotBeforeUpdate() only.37      */38      // const spySnapshot = sinon.spy(EmptyShapshotMethod.prototype, "getSnapshotBeforeUpdate")39      // const spyDidUpdate = sinon.spy(EmptyShapshotMethod.prototype, "componentDidUpdate")40      const username = { "username": "Tony" }41      const wrapper = mount(<EmptyShapshotMethod username={username}/>);42      // expect(spySnapshot.notCalled).toBe(true);43      // expect(spyDidUpdate.notCalled).toBe(true)44      45      wrapper.setProps({ username: "Count Dracula" })46      // expect(spySnapshot.calledOnce).toBe(true);47      // expect(spyDidUpdate.calledOnce).toBe(true)48      // expect(Array.isArray(spySnapshot.returnValues)).toBe(true) // returns [Array[]]49      // expect(spySnapshot.returnValues[0]).toBe(spyDidUpdate.args[0][2])50    });51   it('testing getSnapshotBeforeUpdate(prevProps, prevState) on values returned', () => {52    // taken from react docs 16.453    class ScrollingList extends React.Component {54      constructor(props) {55        super(props);56        this.state = {57          endlessScroll: false58        }59      }60      getSnapshotBeforeUpdate(prevProps, prevState) {61        return prevProps.list.length < this.props.list.length 62          ? this.props.list.length - prevProps.list.length63          : null64      }65      componentDidUpdate(prevProps, prevState, snapshot) {66        if (snapshot !== null) {67          const scrollability = this.state;68          scrollability.endlessScroll = true;69        }70      }71      render() {72        return (73          <div>{/* ...contents... */}</div>74        );...

ScrollingList.js

Source: ScrollingList.js

...3  constructor(props){4      super(props)5      this.listRef = React.createRef();6  }7  getSnapshotBeforeUpdate(prevProps, prevState){8      //æä»¬æ¯å¦è¦æ·»å æ°çitemså°åè¡¨ï¼9      //æææ»å¨æ¡ä½ç½®ï¼ä»¥ä¾¿æä»¬å¯ä»¥ç¨åè°æ´æ»å¨10      if(prevProps.list.length < this.props.list.length){11          const list = this.listRef.current;12          return list.scrollHeight - list.scrollTop13      }14      return null;15  }16  componentDidUpdate(prevProps,prevState,snapshot){17      //å¦ææä»¬æsnapshotå¼ï¼æä»¬å äºæ°çitems18      //è°æ´æ»å¨ä»¥è³äºè¿äºæ°çitems ä¸ä¼å°æ§çitemsæ¨åºè§å¾19      if(snapshot != null){20          const list = this.listRef.current;21          list.scrollTop = list.scrollHeight - snapshot;...

Using AI Code Generation

1import React from 'react';2import { storiesOf } from '@storybook/react';3import { action } from '@storybook/addon-actions';4import Button from './Button';5storiesOf('Button', module)6  .add('with text', () => (7    <Button onClick={action('clicked')}>Hello Button</Button>8  .add('with some emoji', () => (9    <Button onClick={action('clicked')}>😀 😎 👍 💯</Button>10  ));11import React from 'react';12import PropTypes from 'prop-types';13class Button extends React.Component {14  constructor(props) {15    super(props);16    this.state = {17    };18  }19  static propTypes = {20  };21  static defaultProps = {22  };23  componentDidMount() {24    this.interval = setInterval(() => {25      this.setState({ count: this.state.count + 1 });26    }, 1000);27  }28  componentWillUnmount() {29    clearInterval(this.interval);30  }31  getSnapshotBeforeUpdate(prevProps, prevState) {32    return prevState.count;33  }34  componentDidUpdate(prevProps, prevState, snapshot) {35    const { count } = this.state;36    if (count !== snapshot) {37      console.log(`count is now ${count}`);38    }39  }40  render() {41    return (42      <button onClick={this.props.onClick}>43        {this.props.children} {this.state.count}44    );45  }46}47export default Button;48import React from 'react';49import { storiesOf } from '@storybook/react';50import { action } from '@storybook/addon-actions';51import Button from './Button';52storiesOf('Button', module)53  .add('with text', () => (54    <Button onClick={action('clicked')}>Hello Button</Button>55  .add('with some emoji', () => (56    <Button onClick={action('clicked')}>😀 😎 👍 💯</Button>57  ));58import React

Using AI Code Generation

1import React from 'react';2import { storiesOf } from '@storybook/react';3import { action } from '@storybook/addon-actions';4import { withInfo } from '@storybook/addon-info';5import { withKnobs, text, boolean, number } from '@storybook/addon-knobs/react';6import { withReadme, withDocs } from 'storybook-readme';7import { withScreenshot } from 'storycap';8import { Button } from '../src';9import readme from '../README.md';10import ButtonReadme from '../src/Button/README.md';11import ButtonDocs from './Button.md';12const stories = storiesOf('Button', module);13  .addDecorator(withKnobs)14  .addDecorator(withReadme(readme))15  .addDecorator(withDocs(ButtonDocs))16  .addDecorator(withScreenshot());17stories.add('Basic Button', withInfo()(() => <Button>Basic Button</Button>));18stories.add('Button with knobs', withInfo()(() => (19    disabled={boolean('Disabled', false)}20    onClick={action('clicked')}21    variant={text('Variant', 'primary')}22    size={text('Size', 'medium')}23    block={boolean('Block', false)}24    {text('Label', 'Button')}25)));26stories.add('Button with readme', withInfo(ButtonReadme)(() => (27)));28stories.add('Button with screenshot', () => (29));30stories.add('Button with readme and screenshot', withInfo(ButtonReadme)(() => (31)));32stories.add('Button with docs and screenshot', withDocs(ButtonDocs)(() => (33)));34stories.add('Button with readme, docs and screenshot', withInfo(ButtonReadme)(withDocs(ButtonDocs)(() => (35))));

Using AI Code Generation

1import React from 'react';2import { getSnapshotBeforeUpdate } from 'storybook-root';3export const MyComponent = () => {4  const [count, setCount] = React.useState(0);5  const [isMounted, setIsMounted] = React.useState(false);6  const [snapshot, setSnapshot] = React.useState(null);7  React.useEffect(() => {8    setIsMounted(true);9  }, []);10  const handleClick = () => {11    setCount(count + 1);12  };13  React.useEffect(() => {14    if (isMounted) {15      const snapshot = getSnapshotBeforeUpdate();16      setSnapshot(snapshot);17    }18  }, [count]);19  return (20      <button onClick={handleClick}>Click</button>21      <div>Count: {count}</div>22      <div>Snapshot: {JSON.stringify(snapshot)}</div>23  );24};25import React from 'react';26import { getSnapshotAfterUpdate } from 'storybook-root';27export const MyComponent = () => {28  const [count, setCount] = React.useState(0);29  const [isMounted, setIsMounted] = React.useState(false);30  const [snapshot, setSnapshot] = React.useState(null);31  React.useEffect(() => {32    setIsMounted(true);33  }, []);34  const handleClick = () => {35    setCount(count + 1);36  };37  React.useEffect(() => {38    if (isMounted) {39      const snapshot = getSnapshotAfterUpdate();40      setSnapshot(snapshot);41    }42  }, [count]);43  return (44      <button onClick={handleClick}>Click</button>45      <div>Count: {count}</div>46      <div>Snapshot: {JSON.stringify(snapshot)}</div>47  );48};

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