[Bug] this.getLocale() is undefined in index.esm.js and index.js file

[jerome-smith]

Vue2-datepicker version:
3.11.1
Vue version:
2.7.10
Browser:
CHROME
Steps to reproduce
in the browser clicking on the input that launches the datepicker nothing happens;
looking at the browser console the following error is raised

this.getLocale() is undefined

Reproduction Link or Source Code
/node_modules/vue2-datepicker/index.esm.js line 1109

computed: {
    firstDayOfWeek: function firstDayOfWeek() {
      return this.getLocale().formatLocale.firstDayOfWeek || 0;
    },
    yearMonth: function yearMonth() {
      var _this$getLocale = this.getLocale(),
          yearFormat = _this$getLocale.yearFormat,
          monthBeforeYear = _this$getLocale.monthBeforeYear,
          _this$getLocale$month = _this$getLocale.monthFormat,
          monthFormat = _this$getLocale$month === void 0 ? 'MMM' : _this$getLocale$month;

Expected behavior
for this.getLocale() to be present and not be undefined;

Actual behavior
this.getLocale() is undefined