反应日期与时刻js的日期差异

Question

您好我想显示两个日期之间的差异，我从react-dates到momentjs得到。日期显示，但const Diff显示NaN。我根据momentjs https://momentjs.com/docs/#/displaying/difference/的文档做了一切

import React, { Component } from 'react';
import {Col,Grid, Image,Row, Form, ControlLabel, Button} from 'react-bootstrap'
import momentPropTypes from 'react-moment-proptypes';
import moment from 'moment';
import 'react-dates/initialize';
import { DateRangePicker } from 'react-dates';
import 'react-dates/lib/css/_datepicker.css';
moment.locale('pt-br');

class Details extends Component {

constructor (props){
  super(props)
  this.state={
    startDate: "",
    endDate: "",
    focusedInput: "",
  }
render() {
    const endDateString = this.state.endDate && this.state.endDate.format('DD-MM-YYYY');
    const startDateString = this.state.startDate && this.state.startDate.format('DD-MM-YYYY');
    const startDateArr = startDateString.split("-");
    const endDateArr = endDateString.split("-");
    const a = moment(startDateArr);
    const b = moment(endDateArr);
    const Diff =  a.diff(b, 'days');

    return (
      <div>
         <DateRangePicker
                          startDate={this.state.startDate} // momentPropTypes.momentObj or null,
                          endDate={this.state.endDate} // momentPropTypes.momentObj or null,
                          onDatesChange={({ startDate, endDate }) => this.setState({ startDate, endDate })} // PropTypes.func.isRequired,
                          focusedInput={this.state.focusedInput} // PropTypes.oneOf([START_DATE, END_DATE]) or null,
                          onFocusChange={focusedInput => this.setState({ focusedInput })} // PropTypes.func.isRequired,
                          endDatePlaceholderText={"Bis"}
                          startDatePlaceholderText={"Ab"}
                          displayFormat={"DD/MM/YYYY"}
                        />
                      {startDateString}
                      <br/>
                      {endDateString}
                      <br/>
                      {Diff}
     </div>
  )}
}

Answer 1

如果你看一下moment docs用于从数组中构建一个时刻对象，那么顺序是[年，月，日......]，但是你提供的是[日，月，年]。如果您将格式调用更改为'YYYY-MM-DD'，我认为您的代码可以正常工作。

Answer 2

当您尝试使用moment.js函数时，请确保将它们作为时刻对象。我这样用它

let date1=moment();
let date2=moment().add(3,"days");
let daysSpan={moment(date2).diff(moment(date1), 'days')};

这将返回3。