'ValueChanging' does not exist in type 'Readonly <{}>'

Question

I am trying to implement a handler in React for a survey conducted in SurveyJS. This applies to multiple-choice questions that may be answered by answers such as "None of the above" or "Prefer not to answer." If one of these answers is selected, all other answers should be silenced, and if another answer is selected, these flags should be cleared. I deal with one of them individually, but I have problems with the question of where both options are present, especially when switching between two special parameters.

I think that when one answer starts the handler and unchecks the other flag, it starts the handler again. My solution is to set a state indicating when the handler is in the middle of this process, and not do it again at this time.

I got a JS solution for this here: https://github.com/surveyjs/editor/issues/125 - and below is my attempt to convert it to React. (Only relevant parts of the code are included.)

However, when compiling it gives the following error:

ERROR in [at-loader] ./ src / components / Survey / SurveyContainer.tsx: 55: 19 TS2339: the property 'ValueChanging' does not exist by type '& Readonly l; {}>.

I can not find anything about this particular error. Other references to the state (i.e. where I install it) work. Why can't I read it?

Thank!

:

import * as React from 'react';
import { Component } from 'react';
import { Survey, surveyStrings } from 'survey-react';
import 'whatwg-fetch';
import Marked from '../Marked';
import * as style from './style';

interface Props {
  surveyJson: object;
  complete: boolean;
  resultMarkdown: string;
  surveyTitle: string;
  sendSurveyAnswers: (answers: object[]) => void;
  noneOfTheAboveHandler: (survey: object, options: object) => void;
}

Survey.cssType = 'standard';
surveyStrings.progressText = '{0}/{1}';
surveyStrings.emptySurvey = '';

export default class SurveyComponent extends Component<Props, {}> {
  render() {
    const { surveyJson, sendSurveyAnswers, complete, surveyTitle, resultMarkdown, noneOfTheAboveHandler } = this.props;
    return (
      <style.Wrapper>
         { surveyJson && (!complete) &&
          <style.SurveyWrapper>
            <style.SurveyTitle>{ surveyTitle }</style.SurveyTitle>
            <style.Survey>
              <Survey
                onValueChanged={ noneOfTheAboveHandler }
                css={ style.surveyStyles }
                json={ surveyJson }
                onComplete={ sendSurveyAnswers }
              />
            </style.Survey>
          </style.SurveyWrapper>
         }
         { complete &&
         <style.Results>
           <Marked content={resultMarkdown} />
         </style.Results>
         }
      </style.Wrapper>
    );
  }
}

:

import * as React from 'react';
import { Component } from 'react';
import { connect } from 'react-redux';
import SurveyComponent from './SurveyComponent';

interface Props {
  id: string;
  surveyJson: object;
  complete: boolean;
  resultMarkdown: string;
  surveyTitle: string;
  getSurveyQuestions: (id: string) => void;
  sendSurveyAnswers: (answers: object[]) => void;
  noneOfTheAboveHandler: (survey: object, options: object) => void;
  clearSurvey: () => void;
}

class SurveyContainer extends Component<Props, {}> {
  constructor(props) {
    super(props);
    this.state = { ValueChanging: false };
  }

  componentDidMount() {
    this.noneOfTheAboveHandler = this.noneOfTheAboveHandler.bind(this);
    this.props.getSurveyQuestions(this.props.id);
  }

  specialValueSelected(options, specialValue) {
    const { question } = options;
    const prevValue = question.prevValue;
    const index = options.value.indexOf(specialValue);
    this.setState({ ValueChanging: true });
    //has special value selected
    if(index > -1) {
      //special value was selected before
      if(prevValue.indexOf(specialValue) > -1) {
        var value = question.value;
        value.splice(index, 1);
        question.value = value;
      } else {
        //special value select just now
        question.value = [specialValue];
      }
    }
    this.setState({ ValueChanging: false });
    return index > -1;
  }

  noneOfTheAboveHandler(survey, options) {
    const none = 'NA';
    const preferNotToAnswer = 'PN';
    const { question } = options;

    if(this.state.ValueChanging) {
      return;
    }

    if (!question || question.getType() !== 'checkbox') {
      return;
    }

    if (!question.prevValue || !options.value) {
      question.prevValue = options.value;
      return;
    }

    if (!this.specialValueSelected(options,none)) {
      this.specialValueSelected(options,preferNotToAnswer);
    }

    question.prevValue = options.value;
  }

  componentWillUnmount() {
    this.props.clearSurvey();
  }

  render() {
    return (
      <SurveyComponent
        noneOfTheAboveHandler={this.noneOfTheAboveHandler}
        {...this.props}
      />
    );
  }
}

const mapStateToProps = (state, ownProps) => ({
  surveyJson: state.survey.json,
  answers: state.survey.answers,
  resultMarkdown: state.survey.resultMarkdown,
  complete: state.survey.complete,
  surveyTitle: state.page && state.page.data ? state.page.data.title : ''
});

const mapDispatchToProps = dispatch => ({
  getSurveyQuestions: id => dispatch({ type: 'GET_SURVEY_QUESTIONS', id }),
  sendSurveyAnswers: answers => dispatch({ type: 'SEND_SURVEY_ANSWERS', answers: answers.data }),
  clearSurvey: () => dispatch({ type: 'CLEAR_SURVEY' })
});

export default connect(
  mapStateToProps,
  mapDispatchToProps
)(SurveyContainer);

Answer 1

, , {}. , React.Component:

interface MyComponentProps { /* declare your component props here */ }
interface MyComponentState { ValueChanging :  boolean }

class MyComponent extends React.Component<MyComponentProps, MyComponentState> {
  constructor(props) {
  ...

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