How to format Angular Material date-picker inside Formly form for service layer (not display format)

Question

I would like to expose my date value as date only ("yyyy-MM-dd") on an Angular Material date picker. Currently, the default date value is an ISO format (includes time).

I have a starter Stackblitz project with the the required setup. The formly-datepicker.type is where I would like to centralize the conversion so that any date used in the model will be formatted properly for the service layer.

One of my attempts to accomplish it in a centralized manner is using the Angular ControlValueAccessor, but the value is never updated. ControlValueAccessor Stackblitz

In the example Stackblitz, after changing the date and clicking Submit the value I need returned would be something like: {"mydate":"1940-03-11"}(without the time information).

Answer 1

So , I think I have solution for you to display mat datepicker as ("yyyy-MM-dd") format. To do that Install to dependencies "@angular/material-moment-adapter": "^11.1.2" and "moment": "^2.18.1" (both are current version). Then import in your formly-datepicker-type.component.ts file these 2 libraries.

import {MomentDateAdapter} from '@angular/material-moment-adapter';
import {DateAdapter, MAT_DATE_FORMATS, MAT_DATE_LOCALE} from '@angular/material/core';

Then add a date format like below in your formly-datepicker-type.component.ts file.=>

export const MY_FORMATS = {
  parse: {
    dateInput: 'LL',
  },
  display: {
    dateInput: 'YYYY-MM-DD',
    monthYearLabel: 'YYYY',
    dateA11yLabel: 'LL',
    monthYearA11yLabel: 'YYYY',
  },
};

After that Update @Component by adding providers like below =>

@Component({
  selector: "app-formly-datepicker-type",
  templateUrl: "./formly-datepicker-type.component.html",
  styleUrls: ["./formly-datepicker-type.component.css"],
   providers: [
    {provide: DateAdapter, useClass: MomentDateAdapter, deps: [MAT_DATE_LOCALE]},

    {provide: MAT_DATE_FORMATS, useValue: MY_FORMATS},
  ]
}) 

Finally, Date time will show as wanted.
Note: I have updated you sample code of stackblitz. Please check my demo link =>Stackblitz mat-datepicker Date-Time Format.

Answer 2

To adapt the format of the date stored in the model that comes from the datepicker, we can use parsers:

Array of functions to execute, as a pipeline, whenever the model updates, usually via user input.

Example:

// Converts the date value to 'YYYY-MM-DD' string
dateParser(value: any) {
    if (value instanceof Date) {
        return value.toISOString().split('T')[0];
    }
    return value;
}

// Formly field with the dateParser
fields: FormlyFieldConfig[] = [{
    key: 'date',
    type: 'datepicker',
    parsers: [this.dateParser]
}];