Passing Data between react components

Question

I am trying to make simple calendar. In my calendar, I have day, day-names, month and month-names component and all I am accessing it on main calendar. When initial load it will show current month calendar.

Now when I select month from month-name component want to pass to month component and then pass to day component to render dates.

I try to use call back function but it is not helping me out

Whole react component is here https://stackblitz.com/edit/react-ts-z2278r

Day component

import * as moment from 'moment'
import * as React from 'react'

import { showComponent } from '../../../../models'
import { MonthNames } from './'
import styles from './Calendar.module.scss'

interface IDatePickerMonthsProps {
  changeMonthComponent: (showComponent: showComponent, monthNo: number) => void
}

interface IDatePickerMonthsState {
  dateObject: moment.Moment,
  monthNo?: number
}

export class DatePickerMonths extends React.Component<IDatePickerMonthsProps, IDatePickerMonthsState> {

  constructor(props: IDatePickerMonthsProps) {
    super(props)
    this.state = {
      dateObject: moment()
    }
  }

  public render() {
    const monthPicker =
      <div className="datepicker-days">
        <table className={styles.table}>
          <thead>
            <tr>
              <th><span className="ms-Icon ms-Icon--ChevronLeft" title="Previous Month" onClick={this.onPrev}></span></th>
              <th className={styles["picker-switch"]} data-action="pickerSwitch" colSpan={5} title="Select Month">
                {this.year()}
              </th>
              <th><span className="ms-Icon ms-Icon--ChevronRight" title="Next Month" onClick={this.onNext}></span></th>
            </tr>
          </thead>
          <tbody>
            <tr>
              <td colSpan={7}>
                <MonthNames changeMonthComponent={() => this.showDays(this.state.monthNo)} />
              </td>
            </tr>
          </tbody>
        </table>
      </div>

    return (monthPicker)
  }

  private year = () => {
    return this.state.dateObject.format("Y");
  };

  private onPrev = () => {
    this.setState({
      dateObject: this.state.dateObject.subtract(1, "year")
    });
  };
  private onNext = () => {
    this.setState({
      dateObject: this.state.dateObject.add(1, "year")
    });
  };

  private showDays = (monthNo: number) => {
    console.log(monthNo)
    this.setState({ monthNo: monthNo })
    this.props.changeMonthComponent(showComponent.Days, monthNo)
  }
}

Month name component

import * as moment from 'moment'
import * as React from 'react'

import { showComponent } from '../../../../models'

interface IMonthNamesProps {
  changeMonthComponent: (showComponent: showComponent, monthNo: number) => void
}

export class MonthNames extends React.Component<IMonthNamesProps, {}> {
  private monthshort: string[] = moment.monthsShort();

  constructor(props: IMonthNamesProps) {
    super(props)
  }

  public render() {
    let monthshortname = this.monthshort.map((month, monthNo) => {
      return <span key={monthNo} onClick={() => this.showDays(monthNo)}>{month}</span>;
    });
    return monthshortname
  }

  private showDays = (monthNo: number) => {
    this.props.changeMonthComponent(showComponent.Days, monthNo)
  }
}

Month component

import * as moment from 'moment'
import * as React from 'react'

import { showComponent } from '../../../../models'
import { MonthNames } from './'
import styles from './Calendar.module.scss'

interface IDatePickerMonthsProps {
  changeMonthComponent: (showComponent: showComponent, monthNo: number) => void
}

interface IDatePickerMonthsState {
  dateObject: moment.Moment,
  monthNo?: number
}

export class DatePickerMonths extends React.Component<IDatePickerMonthsProps, IDatePickerMonthsState> {

  constructor(props: IDatePickerMonthsProps) {
    super(props)
    this.state = {
      dateObject: moment()
    }
  }

  public render() {
    const monthPicker =
      <div className="datepicker-days">
        <table className={styles.table}>
          <thead>
            <tr>
              <th><span className="ms-Icon ms-Icon--ChevronLeft" title="Previous Month" onClick={this.onPrev}></span></th>
              <th className={styles["picker-switch"]} data-action="pickerSwitch" colSpan={5} title="Select Month">
                {this.year()}
              </th>
              <th><span className="ms-Icon ms-Icon--ChevronRight" title="Next Month" onClick={this.onNext}></span></th>
            </tr>
          </thead>
          <tbody>
            <tr>
              <td colSpan={7}>
                <MonthNames changeMonthComponent={() => this.showDays(this.state.monthNo)} />
              </td>
            </tr>
          </tbody>
        </table>
      </div>

    return (monthPicker)
  }

  private year = () => {
    return this.state.dateObject.format("Y");
  };

  private onPrev = () => {
    this.setState({
      dateObject: this.state.dateObject.subtract(1, "year")
    });
  };
  private onNext = () => {
    this.setState({
      dateObject: this.state.dateObject.add(1, "year")
    });
  };

  private showDays = (monthNo: number) => {
    console.log(monthNo)
    this.setState({ monthNo: monthNo })
    this.props.changeMonthComponent(showComponent.Days, monthNo)
  }
}

Answer 1

See this bit: <MonthNames changeMonthComponent={() => this.showDays(this.state.monthNo)} />

and this bit: this.props.changeMonthComponent(showComponent.Days, monthNo)

The problem there is that the inner component calls the function changeMonthComponent, but the arguments are thrown away by the parent. The MonthNames component needs to do something with the arguments getting passed back up:

<MonthNames changeMonthComponent={(days, monthNo) => this.showDays(monthNo)} />

(Roughly - I'm not digging into all aspects of your code, so I don't know exactly what you want to do with the days parameter that my suggestion is ignoring.)