angular-value-accessor.ts

/* eslint-disable @typescript-eslint/no-unused-vars */
import {EventEmitter, forwardRef} from '@angular/core';
import {
  ControlValueAccessor as Control,
  NG_VALUE_ACCESSOR,
} from '@angular/forms';

export const VALUE_ACCESSOR = <T>(clazz: T) => ({
  provide: NG_VALUE_ACCESSOR,
  useExisting: forwardRef(() => clazz),
  multi: true,
});

export class ControlValueAccessor<T = any> implements Control {
  value?: T;
  valueChange: EventEmitter<T>;

  onChange = (value: T) => undefined;
  onTouched = (value: T) => undefined;

  writeValue(value: T): void {
    this.value = value || this.value;
  }

  pushChanges(value: T) {
    this.onChange(value);
  }

  registerOnChange(fn: (value: T) => undefined): void {
    this.onChange = fn;
  }
  registerOnTouched(fn: (value: T) => undefined): void {
    this.onTouched = fn;
  }
}