How to limit Angular Material multiple select items to N items?

Question

In using https://material.angular.io/components/select/overview#multiple-selection

How to limit the number of items selected to N number? Where N is 3 or 4 or 5.

Answer 1

Set the selectionChange output event on the mat-select component, point it to your component function: (selectionChange)="changed()".

snippet:

In your component create a global variable named mySelections. This will store your selections :) It will hold an array of strings.

It looks like this:

mySelections: string[];

changed() {
  if (this.toppings.value.length < 3) {
    this.mySelections = this.toppings.value;
  } else {
    this.toppings.setValue(this.mySelections);
  }
}

Change the number 3 to N and presto, you're done.