_renderWeekHeader() {
    const weekHeaderStyle = {
      ...defaultStyle.weekHeaderStyle,
      ...this.props.weekHeaderStyle,
    };

    let dayLabelStyle = {
      ...defaultStyle.dayLabelStyle,
      ...this.props.dayLabelStyle,
    };
    if (this.props.disabled) {
      dayLabelStyle = {
        ...dayLabelStyle,
        ...defaultStyle.disabledDayLabelStyle,
        ...this.props.disabledDayLabelStyle,
      };
    }

    const weekendLabelStyle = {
      ...dayLabelStyle,
      ...defaultStyle.weekendLabelStyle,
      ...this.props.weekendLabelStyle,
    };
    let dayNames = shift(this.localeData.dayNamesMin, this.localeData.firstDay);
    dayNames = this.localeData.isRTL ? reverse(dayNames) : dayNames;
    let weekendIndex = ((7 - this.localeData.firstDay) % 7) + this.localeData.weekEnd;
    weekendIndex = this.localeData.isRTL ? 6 - weekendIndex : weekendIndex;

    return (
      <div
        style={ weekHeaderStyle }
        { ...this.weekHeaderProps }
      >
        {
          map(dayNames, (dayAbbr, index) => ((
            <span
              key={ `dayAbbr-${index}` }
              style={ index === weekendIndex ? weekendLabelStyle : dayLabelStyle }
              role="columnheader"
              { ...this.dayLabelProps }
            >
              { dayAbbr }
            </span>
          )))
        }
      </div>
    );
  }
Function will return jsx for rendering the week header for calendar.
Disabled styles will be applied for disabled date-picker.
Day headers will be rendered using locale information.