Modal mode : month localization not working

[AlexandreChollet]

Ionic version: (check one with "x")
[ ] 2.x
[ ] 3.x
[x] 4.x

Ion2-calendar mode: (check one with "x")
[ ] components mode
[x] modal mode

I'm submitting a ... (check one with "x")
[ ] bug report
[x] feature request
[ ] help me

Current behavior:
Localization is not available for months in modal mode.

Expected behavior:
Even when setting 'fr-FR' as localization in my app.module.ts, I cannot get the right month labels in the modal mode.
Why on earth isn't there customization not available, just like the weekdays option?

screenshot

Steps to reproduce:
Open modal.

Related code:

app.module.ts :

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

@NgModule({
  [...]
  providers: [
    { provide: LOCALE_ID, useValue: "fr-FR" }
  ]
})

date-form.ts :

@Input()
calendarModalOptions: CalendarModalOptions;

setOptions() {
    this.calendarModalOptions.weekdays = ['Dim.', 'Lundi', 'Mardi', 'Mercr.', 'Jeudi', 'Vend.', 'Sam.'];
    this.calendarModalOptions.weekStart = 1;
    this.calendarModalOptions.closeIcon = true;
    this.calendarModalOptions.doneIcon = true;
    this.calendarModalOptions.monthFormat = 'MMMM YYYY';
}

Other information:

Ionic info: (run ionic info from a terminal/cmd prompt and paste output below):

Ionic:

   ionic (Ionic CLI)  : 4.12.0
   Ionic Framework    : ionic-angular 3.9.2
   @ionic/app-scripts : 3.2.4

Cordova:

   cordova (Cordova CLI) : not installed
   Cordova Platforms     : not available
   Cordova Plugins       : not available

System:

   NodeJS : v12.18.4 (C:\Program Files\nodejs\node.exe)
   npm    : 6.14.6
   OS     : Windows 10

PS C:\Users\alexandre.chollet\Desktop\Projets\masante\ma-sante>

[JuanGalindoBM]

add this in yout app.component.ts

import * as moment from 'moment';
moment.locale('es');