ngx-calendar-ionic

Notes

version >= 0.3.8 support of ionic 5 && angular 10 (ivy)
version >= 0.4.2 new mode allday view

Usage

Import the NgxCalendarModule module:

import { NgModule } from '@angular/core';
import { IonicApp, IonicModule } from '@ionic/angular';
import { MyApp } from './app/app.component';
import {NgxCalendarModule} from 'ngx-calendar-ionic';


@NgModule({
    declarations: [
        MyApp
    ],
    imports: [
        NgxCalendarModule,
        IonicModule.forRoot(MyApp)
    ],
    bootstrap: [IonicApp],
    entryComponents: [
        MyApp
    ]
})
export class AppModule {}

Import ngxCalendar.scss in global.css

   @import "~ngx-calendar-ionic/ngxCalendar";

Add the directive in the html page

    <calendar [eventSource]="eventSource"
        [calendarMode]="calendar.mode"
        [currentDate]="calendar.currentDate"
        (onCurrentDateChanged)="onCurrentDateChanged($event)"
        (onRangeChanged)="reloadSource(startTime, endTime)"
        (onEventSelected)="onEventSelected($event)"
        (onTitleChanged)="onViewTitleChanged($event)"
        (onTimeSelected)="onTimeSelected($event)"
        (CalendarRefresh)="doRefreshDiv($event)"
        [loading]="!loadDataEventInit"
        [allDayLabel]="allDayLabel"
        [WithoutHours]="calendar.withoutHours"
        step="30">
        
    </calendar>

Options

• loading
  show progress bar when data loaded
• WithoutHours
  new mode to presente allday rdv inday and week view
• formatDay
  The format of the date displayed in the month view.
  Default value: 'dd'
• formatDayHeader
  The format of the header displayed in the month view.
  Default value: 'EEE'
• formatDayTitle
  The format of the title displayed in the day view.
  Default value: 'MMMM dd, yyyy'
• formatWeekTitle
  The format of the title displayed in the week view.
  Default value: (version 0.1-0.3) 'MMMM yyyy, Week $n', (version 0.4+) 'MMMM yyyy, 'Week' w'
• formatMonthTitle
  The format of the title displayed in the month view.
  Default value: 'MMMM yyyy'
• formatWeekViewDayHeader
  The format of the header displayed in the week view.
  Default value: 'EEE d'
• formatHourColumn
  The format of the hour column displayed in the week and day view.
  Default value: (version 0.1-0.3) 'j', (version 0.4+) 'ha'
• calendarMode
  The initial mode of the calendar.
  Default value: 'month'
• showEventDetail
  If set to true, when selecting the date in the month view, the events happened on that day will be shown below.
  Default value: true
• startingDayMonth
  Control month view starting from which day.
  Default value: 0
• startingDayWeek
  Control week view starting from which day.
  Default value: 0
• allDayLabel
  The text displayed in the allDay column header.
  Default value: 'all day'
• noEventsLabel
  The text displayed when there’s no event on the selected date in month view.
  Default value: 'No Events'
• eventSource
  The data source of the calendar, when the eventSource is set, the view will be updated accordingly.
  Default value: null
  The format of the eventSource is described in the EventSource section
• queryMode
  If queryMode is set to 'local', when the range or mode is changed, the calendar will use the already bound eventSource to update the view
  If queryMode is set to 'remote', when the range or mode is changed, the calendar will trigger a callback function rangeChanged.
  Users will need to implement their custom loading data logic in this function, and fill it into the eventSource. The eventSource is watched, so the view will be updated once the eventSource is changed.
  Default value: 'local'
• step
  It is used to display the event using more accurate time interval in weekview and dayview. For example, if set to 30, then the event will only occupy half of the row height (If timeInterval option uses default value). The unit is minute. It can be set to 15 or 30.
  Default value: 60

        <calendar ... [step]="30"></calendar>

• timeInterval (version >= 0.3)
  It is used to display the rows using more accurate time interval in weekview and dayview. For example, if set to 30, then the time interval between each row is 30 mins. The unit is minute. It should be the factor or multiple of 60, which means 60%timeInterval=0 or timeInterval%60=0.
  Default value: 60

        <calendar ... [timeInterval]="30"></calendar>

• autoSelect
  If set to true, the current calendar date will be auto selected when calendar is loaded or swiped in the month and week view.
  Default value: true
• locale
  The locale used to display text in the calendar.
  Default value: undefined (which means the local language)

    <calendar ... [locale]="calendar.locale"></calendar>

    calendar = {
        locale: 'en-GB'
    };

• markDisabled
  The callback function used to determine if the time should be marked as disabled.

    <calendar ... [markDisabled]="markDisabled"></calendar>

    markDisabled = (date: Date) => {
        var current = new Date();
        return date < current;
    };

• intervalDisabled
  The callback function used to determine if the day hour should be marked as disabled .

    <calendar ... [intervalDisabled]="intervalDisabled"></calendar>

    intervalDisabled = (date: Date) => {
        var current = new Date();
        return date < current;
    };

• dateFormatter
  The custom date formatter to transform date to text.
  If the custom date formatter is not set, the default Angular DatePipe is used. The format method in dateFormatter is optional, if omitted, the default Angular DatePipe is used.

    <calendar ... [dateFormatter]="calendar.dateFormatter"></calendar>

    calendar = {
        dateFormatter: {
            formatMonthViewDay: function(date:Date) {
                return date.getDate().toString();
            },
            formatMonthViewDayHeader: function(date:Date) {
                return 'testMDH';
            },
            formatMonthViewTitle: function(date:Date) {
                return 'testMT';
            },
            formatWeekViewDayHeader: function(date:Date) {
                return 'testWDH';
            },
            formatWeekViewTitle: function(date:Date) {
                return 'testWT';
            },
            formatWeekViewHourColumn: function(date:Date) {
                return 'testWH';
            },
            formatDayViewHourColumn: function(date:Date) {
                return 'testDH';
            },
            formatDayViewTitle: function(date:Date) {
                return 'testDT';
            }
        }
    };        

• dir
  If set to "rtl", the calendar supports RTL language. This feature is only supported in Ionic 2.3.0 version onwards.
  Default value: ""

• scrollToHour
  Make weekview and dayview scroll to the specific hour after entering to the new view.
  Default value: 0

• preserveScrollPosition
  If set to true, the previous/next views in weekview and dayview will also scroll to the same position as the current active view.
  Default value: false

• lockSwipeToPrev
  If set to true, swiping to previous view is disabled.
  Default value: false

    <calendar ... [lockSwipeToPrev]="lockSwipeToPrev"></calendar>

    onCurrentDateChanged(event:Date) {
        var today = new Date();
        today.setHours(0, 0, 0, 0);
        event.setHours(0, 0, 0, 0);

        if (this.calendar.mode === 'month') {
            if (event.getFullYear() < today.getFullYear() || (event.getFullYear() === today.getFullYear() && event.getMonth() <= today.getMonth())) {
                this.lockSwipeToPrev = true;
            } else {
                this.lockSwipeToPrev = false;
            }
        }
    }

• lockSwipes
  If set to true, swiping is disabled.
  Default value: false
  Note: Since swiping is disabled, you could set currentDate to move the calendar to previous/next view. Do not set lockSwipeToPrev in the constructor phase. It will cause the view not updating when changing the currentDate. You could either set it in some callback function after initialization phase or use setTimeout to trigger some delay.

    <calendar ... [lockSwipeToPrev]="lockSwipeToPrev"></calendar>

    ngAfterViewInit() {
        var me = this;
        setTimeout(function() {
            me.lockSwipes = true;
        },100);
    }

• startHour
  Limit the weekview and dayview starts from which hour (0-23).
  Default value: 0

    <calendar ... startHour="9"></calendar>

• endHour
  Limit the weekview and dayview ends until which hour (1-24).
  Default value: 24

    <calendar ... endHour="19"></calendar>

• sliderOptions
  Options to pass to the underlying swiper instance. See http://idangero.us/swiper/api/ for valid options.

    <calendar ... sliderOptions="sliderOptions"></calendar>

    options = {
        spaceBetween: 10,
        threshold: 50
    };

• onCurrentDateChanged
  The callback function triggered when the date that is currently viewed changes.

    <calendar ... (onCurrentDateChanged)="onCurrentDateChanged($event)"></calendar>

    onCurrentChanged = (ev: Date) => {
        console.log('Currently viewed date: ' + ev);
    };

• onRangeChanged
  The callback function triggered when the range or mode is changed if the queryMode is set to 'remote'
  The ev parameter contains two fields, startTime and endTime.

    <calendar ... (onRangeChanged)="onRangeChanged($event)"></calendar>

    onRangeChanged = (ev: { startTime: Date, endTime: Date }) => {
        Events.query(ev, (events) => {
            this.eventSource = events;
        });
    };

• CalendarRefresh
  The callback function triggered when the refresh spinner

    <calendar ... (CalendarRefresh)="CalendarRefresh($event)"></calendar>

    CalendarRefresh = (refresher) => {
        setTimeout(() => {
          console.log('Async operation has ended');
          event.target.complete();
        }, 2000);
    };

• onEventSelected
  The callback function triggered when an event is clicked

    <calendar ... (onEventSelected)="onEventSelected($event)"></calendar>

    onEventSelected = (event) => {
        console.log(event.title);
    };

• onTimeSelected
  The callback function triggered when a date is selected in the monthview.
  The ev parameter contains two fields, selectedTime and events, if there's no event at the selected time, the events field will be either undefined or empty array

    <calendar ... (onTimeSelected)="onTimeSelected($event)"></calendar>

    onTimeSelected = (ev: { selectedTime: Date, events: any[] }) => {
        console.log('Selected time: ' + ev.selectedTime + ', hasEvents: ' + (ev.events !== undefined && ev.events.length !== 0));
    };

• onTitleChanged
  The callback function triggered when the view title is changed

    <calendar ... (onTitleChanged)="onViewTitleChanged($event)"></calendar>

    onViewTitleChanged = (title: string) => {
        this.viewTitle = title;
    };

View Customization Option

There are two ways to customize the look and feel. If you just want to simply change the color or size of certain element, you could override the styles of the predefined css classes. CSS Customization section lists some important css classes. If you need to change the layout of certain element, you could refer to the Template Customization part.

CSS Customization

• monthview-primary-with-event
  The date that is in current month and having events

• monthview-secondary-with-event
  The date that is in previous/next month and having events

• monthview-selected
  The selected date

• monthview-current
  The current date

• monthview-disabled
  The disabled date

• weekview-with-event
  The date having all day events, applied to the day header in week view

• week-view-current
  The current date, applied to the day header in week view

• weekview-selected
  The selected date, applied to the day header in week view

• weekview-allday-label
  Applied to the all day label in week view

• dayview-allday-label
  Applied to the all day label in day view

• calendar-hour-column
  Applied to the hour column in both weekview and day view

Template Customization

Note: For any css class appear in the customized template, you need to specify the styles by yourself. The styles defined in the calendar component won’t be applied because of the view encapsulation. You could refer to calendar.ts to get the definition of context types.

• monthviewDisplayEventTemplate
  Type: TemplateRef<IMonthViewDisplayEventTemplateContext>
  The template provides customized view for event displayed in the active monthview

    <ng-template #template let-view="view" let-row="row" let-col="col">
        {{view.dates[row*7+col].label}}
    </ng-template>

    <calendar ... [monthviewDisplayEventTemplate]="template"></calendar>

• monthviewInactiveDisplayEventTemplate
  Type: TemplateRef<IMonthViewDisplayEventTemplateContext>
  The template provides customized view for event displayed in the inactive monthview

    <ng-template #template let-view="view" let-row="row" let-col="col">
        {{view.dates[row*7+col].label}}
    </ng-template>

    <calendar ... [monthviewInactiveDisplayEventTemplate]="template"></calendar>

• monthviewEventDetailTemplate
  Type: TemplateRef<IMonthViewEventDetailTemplateContext>
  The template provides customized view for event detail section in the monthview

    <ng-template #template let-showEventDetail="showEventDetail" let-selectedDate="selectedDate" let-noEventsLabel="noEventsLabel">
    ... 
    </ng-template>

    <calendar ... [monthviewEventDetailTemplate]="template"></calendar>

• weekviewHeaderTemplate (version >= 0.4.5)
  Type: TemplateRef<IDisplayWeekViewHeader>
  The template provides customized view for day header in the weekview

    <ng-template #template let-viewDate="viewDate"> 
        <div class="custom-day-header"> {{ viewDate.dayHeader }} </div> 
    </ng-template> 
 
    <calendar ... [weekviewHeaderTemplate]="template"></calendar>

• weekviewAllDayEventTemplate
  Type: TemplateRef<IDisplayAllDayEvent>
  The template provides customized view for all day event in the weekview

    <ng-template #template let-displayEvent="displayEvent">
        <div class="calendar-event-inner">{{displayEvent.event.title}}</div>
    </ng-template>

    <calendar ... [weekviewAllDayEventTemplate]="template"></calendar>

• weekviewNormalEventTemplate
  Type: TemplateRef<IDisplayEvent>
  The template provides customized view for normal event in the weekview

    <ng-template #template let-displayEvent="displayEvent">
        <div class="calendar-event-inner">{{displayEvent.event.title}}</div>
    </ng-template>

    <calendar ... [weekviewNormalEventTemplate]="template"></calendar>

• dayviewAllDayEventTemplate
  Type: TemplateRef<IDisplayAllDayEvent>
  The template provides customized view for all day event in the dayview

    <ng-template #template let-displayEvent="displayEvent">
        <div class="calendar-event-inner">{{displayEvent.event.title}}</div>
    </ng-template>

    <calendar ... [dayviewAllDayEventTemplate]="template"></calendar>

• dayviewNormalEventTemplate
  Type: TemplateRef<IDisplayEvent>
  The template provides customized view for normal event in the dayview

    <ng-template #template let-displayEvent="displayEvent">
        <div class="calendar-event-inner">{{displayEvent.event.title}}</div>
    </ng-template>

    <calendar ... [dayviewNormalEventTemplate]="template"></calendar>

• weekviewAllDayEventSectionTemplate (version >= 0.3)
  Type: TemplateRef<IWeekViewAllDayEventSectionTemplateContext>
  The template provides customized view for all day event section (table part) in the weekview

        <ng-template #template let-day="day" let-eventTemplate="eventTemplate">
            <div [ngClass]="{'calendar-event-wrap': day.events}" *ngIf="day.events"
                 [ngStyle]="{height: 25*day.events.length+'px'}">
                <div *ngFor="let displayEvent of day.events" class="calendar-event" tappable
                     (click)="onEventSelected(displayEvent.event)"
                     [ngStyle]="{top: 25*displayEvent.position+'px', width: 100*(displayEvent.endIndex-displayEvent.startIndex)+'%', height: '25px'}">
                    <ng-template [ngTemplateOutlet]="eventTemplate"
                                 [ngTemplateOutletContext]="{displayEvent:displayEvent}">
                    </ng-template>
                </div>
            </div>
        </ng-template>

        <calendar ... [weekviewAllDayEventSectionTemplate]="template"></calendar>

• weekviewNormalEventSectionTemplate (version >= 0.3)
  Type: TemplateRef<IWeekViewNormalEventSectionTemplateContext>
  The template provides customized view for normal event section (table part) in the weekview

        <ng-template #template let-tm="tm" let-hourParts="hourParts" let-eventTemplate="eventTemplate">
            <div [ngClass]="{'calendar-event-wrap': tm.events}" *ngIf="tm.events">
                <div *ngFor="let displayEvent of tm.events" class="calendar-event" tappable
                     (click)="onEventSelected(displayEvent.event)"
                     [ngStyle]="{top: (37*displayEvent.startOffset/hourParts)+'px',left: 100/displayEvent.overlapNumber*displayEvent.position+'%', width: 100/displayEvent.overlapNumber+'%', height: 37*(displayEvent.endIndex -displayEvent.startIndex - (displayEvent.endOffset + displayEvent.startOffset)/hourParts)+'px'}">
                    <ng-template [ngTemplateOutlet]="eventTemplate"
                                 [ngTemplateOutletContext]="{displayEvent:displayEvent}">
                    </ng-template>
                </div>
            </div>
        </ng-template>

        <calendar ... [weekviewNormalEventSectionTemplate]="template"></calendar>

• dayviewAllDayEventSectionTemplate (version >= 0.3)
  Type: TemplateRef<IDayViewAllDayEventSectionTemplateContext>
  The template provides customized view for all day event section (table part) in the dayview

        <ng-template #template let-allDayEvents="allDayEvents" let-eventTemplate="eventTemplate">
            <div *ngFor="let displayEvent of allDayEvents; let eventIndex=index"
                 class="calendar-event" tappable
                 (click)="onEventSelected(displayEvent.event)"
                 [ngStyle]="{top: 25*eventIndex+'px',width: '100%',height:'25px'}">
                <ng-template [ngTemplateOutlet]="eventTemplate"
                             [ngTemplateOutletContext]="{displayEvent:displayEvent}">
                </ng-template>
            </div>
        </ng-template>

        <calendar ... [dayviewAllDayEventSectionTemplate]="template"></calendar>

• dayviewNormalEventSectionTemplate (version >= 0.3)
  Type: TemplateRef<IDayViewNormalEventSectionTemplateContext>
  The template provides customized view for normal event section (table part) in the dayview

        <ng-template #template let-tm="tm" let-hourParts="hourParts" let-eventTemplate="eventTemplate">
            <div [ngClass]="{'calendar-event-wrap': tm.events}" *ngIf="tm.events">
                <div *ngFor="let displayEvent of tm.events" class="calendar-event" tappable
                     (click)="onEventSelected(displayEvent.event)"
                     [ngStyle]="{top: (37*displayEvent.startOffset/hourParts)+'px',left: 100/displayEvent.overlapNumber*displayEvent.position+'%', width: 100/displayEvent.overlapNumber+'%', height: 37*(displayEvent.endIndex -displayEvent.startIndex - (displayEvent.endOffset + displayEvent.startOffset)/hourParts)+'px'}">
                    <ng-template [ngTemplateOutlet]="eventTemplate"
                                 [ngTemplateOutletContext]="{displayEvent:displayEvent}">
                    </ng-template>
                </div>
            </div>
        </ng-template>

        <calendar ... [dayviewNormalEventSectionTemplate]="template"></calendar>

• weekviewInactiveAllDayEventSectionTemplate (version >= 0.3)
  Type: TemplateRef<IWeekViewAllDayEventSectionTemplateContext>
  The template provides customized view for all day event section (table part) in the inactive weekview

        <ng-template #template let-day="day" let-eventTemplate="eventTemplate">
            <div [ngClass]="{'calendar-event-wrap': day.events}" *ngIf="day.events"
                 [ngStyle]="{height: 25*day.events.length+'px'}">
                <div *ngFor="let displayEvent of day.events" class="calendar-event" tappable
                     (click)="onEventSelected(displayEvent.event)"
                     [ngStyle]="{top: 25*displayEvent.position+'px', width: 100*(displayEvent.endIndex-displayEvent.startIndex)+'%', height: '25px'}">
                    <ng-template [ngTemplateOutlet]="eventTemplate"
                                 [ngTemplateOutletContext]="{displayEvent:displayEvent}">
                    </ng-template>
                </div>
            </div>
        </ng-template>

        <calendar ... [weekviewInactiveAllDayEventSectionTemplate]="template"></calendar>

• weekviewInactiveNormalEventSectionTemplate (version >= 0.3)
  Type: TemplateRef<IWeekViewNormalEventSectionTemplateContext>
  The template provides customized view for normal event section (table part) in the inactive weekview

        <ng-template #template let-tm="tm" let-hourParts="hourParts" let-eventTemplate="eventTemplate">
            <div [ngClass]="{'calendar-event-wrap': tm.events}" *ngIf="tm.events">
                <div *ngFor="let displayEvent of tm.events" class="calendar-event" tappable
                     (click)="onEventSelected(displayEvent.event)"
                     [ngStyle]="{top: (37*displayEvent.startOffset/hourParts)+'px',left: 100/displayEvent.overlapNumber*displayEvent.position+'%', width: 100/displayEvent.overlapNumber+'%', height: 37*(displayEvent.endIndex -displayEvent.startIndex - (displayEvent.endOffset + displayEvent.startOffset)/hourParts)+'px'}">
                    <ng-template [ngTemplateOutlet]="eventTemplate"
                                 [ngTemplateOutletContext]="{displayEvent:displayEvent}">
                    </ng-template>
                </div>
            </div>
        </ng-template>

        <calendar ... [weekviewInactiveNormalEventSectionTemplate]="template"></calendar>

• dayviewInactiveAllDayEventSectionTemplate (version >= 0.3)
  Type: TemplateRef<IDayViewAllDayEventSectionTemplateContext>
  The template provides customized view for all day event section (table part) in the inactive dayview

        <ng-template #template let-allDayEvents="allDayEvents" let-eventTemplate="eventTemplate">
            <div *ngFor="let displayEvent of allDayEvents; let eventIndex=index"
                 class="calendar-event" tappable
                 (click)="onEventSelected(displayEvent.event)"
                 [ngStyle]="{top: 25*eventIndex+'px',width: '100%',height:'25px'}">
                <ng-template [ngTemplateOutlet]="eventTemplate"
                             [ngTemplateOutletContext]="{displayEvent:displayEvent}">
                </ng-template>
            </div>
        </ng-template>

        <calendar ... [dayviewInactiveAllDayEventSectionTemplate]="template"></calendar>

• dayviewInactiveNormalEventSectionTemplate (version >= 0.3)
  Type: TemplateRef<IDayViewNormalEventSectionTemplateContext>
  The template provides customized view for normal event section (table part) in the inactive dayview

        <ng-template #template let-tm="tm" let-hourParts="hourParts" let-eventTemplate="eventTemplate">
            <div [ngClass]="{'calendar-event-wrap': tm.events}" *ngIf="tm.events">
                <div *ngFor="let displayEvent of tm.events" class="calendar-event" tappable
                     (click)="onEventSelected(displayEvent.event)"
                     [ngStyle]="{top: (37*displayEvent.startOffset/hourParts)+'px',left: 100/displayEvent.overlapNumber*displayEvent.position+'%', width: 100/displayEvent.overlapNumber+'%', height: 37*(displayEvent.endIndex -displayEvent.startIndex - (displayEvent.endOffset + displayEvent.startOffset)/hourParts)+'px'}">
                    <ng-template [ngTemplateOutlet]="eventTemplate"
                                 [ngTemplateOutletContext]="{displayEvent:displayEvent}">
                    </ng-template>
                </div>
            </div>
        </ng-template>

        <calendar ... [dayviewInactiveNormalEventSectionTemplate]="template"></calendar>

EventSource

EventSource is an array of event object which contains at least below fields:

• title
• startTime
  If allDay is set to true, the startTime has to be as a UTC date which time is set to 0:00 AM, because in an allDay event, only the date is considered, the exact time or timezone doesn't matter.
  For example, if an allDay event starting from 2014-05-09, then startTime is

    var startTime = new Date(Date.UTC(2014, 4, 8));

• endTime     If allDay is set to true, the startTime has to be as a UTC date which time is set to 0:00 AM, because in an allDay event, only the date is considered, the exact time or timezone doesn't matter.
  For example, if an allDay event ending to 2014-05-10, then endTime is

    var endTime = new Date(Date.UTC(2014, 4, 9));

• allDay     Indicates the event is allDay event or regular event

Note The calendar only watches for the eventSource reference for performance consideration. That means only you manually reassign the eventSource value, the calendar gets notified, and this is usually fit to the scenario when the range is changed, you load a new data set from the backend. In case you want to manually insert/remove/update the element in the eventSource array, you can call instance method ‘loadEvents’ event to notify the calendar manually.

Instance Methods

• loadEvents
  When this method is called, the calendar will be forced to reload the events in the eventSource array. This is only necessary when you directly modify the element in the eventSource array.

import { CalendarComponent } from "ngx-calendar-ionic/calendar";

@Component({
    selector: 'page-home',
    templateUrl: 'home.html'
})
export class HomePage {
    @ViewChild(CalendarComponent) myCalendar:CalendarComponent;
    eventSource;
    …
    loadEvents: function() {
        this.eventSource.push({
            title: 'test',
            startTime: startTime,
            endTime: endTime,
            allDay: false
        });
        this.myCalendar.loadEvents();
    }
}

Localization

You could use locale option to achieve the localization.
If locale option is not specified, the calendar will use the LOCALE_ID set at the module level.
By default, the LOCALE_ID is en-US. You can override it in the module as below. If you pass undefined, the LOCALE_ID will be detected using the browser language setting. But using explicit value is recommended, as browser has different level of localization support.
Note that the event detail section in the month view doesn't support locale option, only LOCALE_ID takes effect. This is because it uses DatePipe in html directly. You could easily leverage customized event detail template to switch to other locale.

import { NgModule, LOCALE_ID } from '@angular/core';

@NgModule({
    …
    providers: [
        { provide: LOCALE_ID, useValue: 'zh-CN' }
    ]
})

For version 0.4.x+ which depends on Ionic 3.9.2+ and Angular 5.0+, locale module needs to be registered explicitly in module file as below.

import { registerLocaleData } from '@angular/common';
import localeZh from '@angular/common/locales/zh';
registerLocaleData(localeZh);

If you want to change the locale dynamically, you should use locale option instead of LOCALE_ID.

Performance Tuning

In the CPU profile, the default Intl based localization code occupies a big portion of the execution time. If you don’t need localization on certain parts, you can use the custom dateFormatter to override the date transform method. For example, the date in month view usually doesn’t require localization, you could use below code to just display the date part. If the month view day header doesn’t need to include the date, you could also use a string array containing static labels to save the date calculation.

<calendar ... [dateFormatter]="calendar.dateFormatter"></calendar>

calendar = {
    dateFormatter: {
        formatMonthViewDay: function(date:Date) {
            return date.getDate().toString();
        }            
    }
};

• How to switch the calendar to previous/next month programmatically?
  Answer: You can change currentDate to the date in previous/next month. You could also retrieve the Swiper element and then call the Swiper API directly.

var mySwiper = document.querySelector('.swiper-container')['swiper'];
    mySwiper.slideNext();