Angular Material Datepicker：如何过滤以便只允许数组中的日期？

Question

I have an array of dates returned from an API. For example, I might have an array entitled validDates that has all of the Mondays in September as their values. I would like to use the Material Datepicker filter to only allow date values in the array to be selected.

Example Date Array

validDates = [
    Mon Sep 02 2019 00:00:00 GMT-0500 (Central Daylight Time),
    Mon Sep 09 2019 00:00:00 GMT-0500 (Central Daylight Time),
    Mon Sep 16 2019 00:00:00 GMT-0500 (Central Daylight Time),
    Mon Sep 23 2019 00:00:00 GMT-0500 (Central Daylight Time),
    Mon Sep 30 2019 00:00:00 GMT-0500 (Central Daylight Time)
]

Datepicker Filter (not working)

myFilter = ( d: Date ): boolean => {
    let dateOpen: boolean;
    for ( let x = 0; x < this.validDates.length; x++ ) {
      dateOpen = d.toString() === this.validDates[ x ].toString();
    }
    return dateOpen;
  }

The issue is it only returns the last date (Mon Sep 30 2019 00:00:00 GMT-0500 (Central Daylight Time)) as true so that only the 30th becomes selectable. I want each of the dates in the array to be selectable.

How can I return true for each value in the array?

Answer 1

To only allow dates within an array, the myFilter method may be defined as follows.

myFilter = (d: Date): boolean => {
  // Only allow dates in `validDates`.
  return this.validDates.findIndex( (valid_date) => d.getTime() === valid_date.getTime()) > -1
}

See Stackblitz Demo

To ignore the time component of the Date , see:
Comparing date part only without comparing time in JavaScript

Answer 2

Finally I found correct solution:

// The array of days of week to be available
const arr = [0, 3, 6];
this.expressSenderDate = (d: Date): boolean => {
    const day = d.getDay();
    // tslint:disable-next-line:align
    return arr.indexOf(day) !== -1;
};