reactjs

问题 When using the npm package " use-dark-mode " I try to apply the hook const darkMode = useDarkMode (false); inside a function but i get an error Error: Invalid hook call. Hooks can only be called inside of the body of a function component. This could happen for one of the following reasons: before giving you the code, I want to explain in more detail, I think you already understood from the package name, I want to use dark mode in my project, I have a lot of components, I pass the dark mode

问题 When using the npm package " use-dark-mode " I try to apply the hook const darkMode = useDarkMode (false); inside a function but i get an error Error: Invalid hook call. Hooks can only be called inside of the body of a function component. This could happen for one of the following reasons: before giving you the code, I want to explain in more detail, I think you already understood from the package name, I want to use dark mode in my project, I have a lot of components, I pass the dark mode

问题 I receive this error: TypeError: this.state is null Have code like this, but it does not work .... Any idea why? I want to change the text of a label (reanalyzeButton) Read several docs and tutorials and it seem it should work. No idea why it behaves like this. This is inherited code I work with using React 0.13 var ProjectHeader = React.createClass({ displayName: 'ProjectHeader', intervalId: null, state: { projectjson: [], label: '', }, componentDidMount() { // Now we need to make it run at

问题 Hi i have problem with my react components. I don't know how to update element in table from shared modal for all elements. In my real case i have students timetable and i have to edit columns with subjects. After I click on subject in table, modal should open and after i choosed which subject i want to input it should change. I prepeared basic model of situation on codeblox. Please how should i access to specific column throught this modal and update that column with value of button. Thx for

问题 OperationSavDetails.js class OperationSavDetails extends Component { constructor(props) { super(props); this.state = { statusUpdateDropDownOpen: false, statusUpdateDropDownValue: "Mettre à jour le status de l'opération SAV" }; this.changeStatusUpdateDropDownValue = this.changeStatusUpdateDropDownValue.bind( this ); this.toggleStatusUpdateDropDown = this.toggleStatusUpdateDropDown.bind( this ); } changeStatusUpdateDropDownValue(e) { console.log("e.currentTarget.textContent"); console.log(e

问题 OperationSavDetails.js class OperationSavDetails extends Component { constructor(props) { super(props); this.state = { statusUpdateDropDownOpen: false, statusUpdateDropDownValue: "Mettre à jour le status de l'opération SAV" }; this.changeStatusUpdateDropDownValue = this.changeStatusUpdateDropDownValue.bind( this ); this.toggleStatusUpdateDropDown = this.toggleStatusUpdateDropDown.bind( this ); } changeStatusUpdateDropDownValue(e) { console.log("e.currentTarget.textContent"); console.log(e

问题 I was searching for a way to set the default font-family for the entire react app but all results/packages point to react native instead. For react is there a way to default a global font setting without specifying font-family in every css? Thanks. 回答1: If I understand your question correctly this should do: @import url(https://fonts.googleapis.com/css?family=Open+Sans); body { font-family: 'Open Sans',serif; } 来源： https://stackoverflow.com/questions/59306327/is-there-a-way-to-set-the-default

问题 I have need to pass a value from a page to another using react-router. I have tried in this way: <li> <A className="btn btn-link btn-sm" href={{ pathname: Routes.detail_page, search: `?_id=${C.Code}`, state: this.props.current }}> { 'Open' } </A> </li> I would pass this.props.current to Detail Page. In the other page if I tried in the componentDidMount() to print this.props.current it result undefined (of course in the first page this value is parametrized). constructor(props){ super(props);

问题 I have a few tags created using styled components lib: component.js .... const NoJobs = styled.h1` text-align: center; `; .... <div> <NoJobs> No Jobs Found!!! </NoJobs> </div> I want to test this component, below is my test case: component.test.js describe('<JobList />', () => { let wrapper; beforeEach(() => { wrapper = shallow(<JobList />); }); it('should show "no data found" when there is no data', () => { expect(wrapper.contains(<NoJobs>No Jobs Found!!!</NoJobs>)).toEqual(true); }); });

问题 How to render options inside select tag in ReactJs? I have a json data for country and state. I want to render states in select tag dynamically with selected country. const onCountryChange = value => { const country = value.split("_")[0]; const countryCode = value.split("_")[1]; const countryId = value.split("_")[2]; setCountry(country); setCountryCode(countryCode); setCountryId(countryId) }; Select tag for country <select value={country} onChange={e => onCountryChange(e.target.value)}>