如何修复 React 中的“TypeError：moment is not a function”？

Question

I've tried downgrading to Moment.js version 2.24.0, but that did not fix my issue. Below is my code. Is there something I'm doing wrong? The error is pointing to my formatDate function, but I can't seem to pinpoint the issue.

import moment from 'moment';

class ViewMorePhotos extends Component {
    state = {
        date: moment(),
        photo: ""
    };
    
    formatDate = moment => {
        let year = moment().year();
        let month = moment().month() + 1;
        let day = moment().date();
        return `${year}-${month}-${day}`;
    };
    
    changeDate = dateFromInput => {
        this.setState({ date: dateFromInput });
        this.getPhoto(this.formatDate(dateFromInput));
    };

    getPhoto = date => {
        fetch( `api-url`)
            .then(response => response.json())
            .then(photoData => this.setState({ photo: photoData }));
    };
    
    render() {
        return (
            <React.Fragment>
                <NavBar />
                <DateInput changeDate={this.changeDate} date={this.state.date} />
                <Photo photo={this.state.photo} />
            </React.Fragment>
        );
    }
}

This is the error I receive:

TypeError: moment is not a function
ViewMorePhotos/this.formatDate
src/components/ViewMorePhotos.js:17

  14 | };
  15 | 
  16 | formatDate = moment => {
> 17 |     let year = moment().year();
     | ^  18 |     let month = moment().month() + 1;
  19 |     let day = moment().date();
  20 |     return `${year}-${month}-${day}`;

ViewMorePhotos/this.changeDate
src/components/ViewMorePhotos.js:25

  22 | 
  23 | changeDate = dateFromInput => {
  24 |     this.setState({ date: dateFromInput });
> 25 |     this.getPhoto(this.formatDate(dateFromInput));
     | ^  26 | };
  27 | 
  28 | getPhoto = date => {

Answer 1

Change your function to

formatDate = aDate => {
    let m = moment(aDate)
    let year = m.year();
    let month = m.month() + 1;
    let day = m.date();
    return `${year}-${month}-${day}`;
};

Not tested but should work.