问Mat-选择用户类型为3-4个字符的角度选项过滤器

EN

<h4>mat-select</h4>
<mat-form-field appearance="fill">
  <mat-label>State</mat-label>
  <mat-select>
    <mat-option>None</mat-option>
    <mat-option *ngFor="let state of states" [value]="state">{{state}}</mat-option>
  </mat-select>
</mat-form-field>

import {Component} from '@angular/core';

/** @title Select with reset option */
@Component({
  selector: 'select-reset-example',
  templateUrl: 'select-reset-example.html',
})
export class SelectResetExample {
  states: string[] = [
    'Alabama', 'Alaska', 'Arizona', 'Arkansas', 'California', 'Colorado', 'Connecticut', 'Delaware',
    'Florida', 'Georgia', 'Hawaii', 'Idaho', 'Illinois', 'Indiana', 'Iowa', 'Kansas', 'Kentucky',
    'Louisiana', 'Maine', 'Maryland', 'Massachusetts', 'Michigan', 'Minnesota', 'Mississippi',
    'Missouri', 'Montana', 'Nebraska', 'Nevada', 'New Hampshire', 'New Jersey', 'New Mexico',
    'New York', 'North Carolina', 'North Dakota', 'Ohio', 'Oklahoma', 'Oregon', 'Pennsylvania',
    'Rhode Island', 'South Carolina', 'South Dakota', 'Tennessee', 'Texas', 'Utah', 'Vermont',
    'Virginia', 'Washington', 'West Virginia', 'Wisconsin', 'Wyoming'
  ];
}