为什么自定义管道不适用于 Angular 2 中的本地模板变量

Question

I have a Pipe just for Example that Squares the value that it receives this below one works fine

Template

<input type = "number" placeholder = "Enter number for which square is to be calculated" [(ngModel)] = "value">
  <p>Squared Number is using pipe Transform  {{value | square}} </p>

Component

value = 2;

Custom Pipe

import { Pipe,PipeTransform } from '@angular/core';

@Pipe({
    name:'square'
})

export class SquarePipe implements PipeTransform{
  transform(value: number, args?: number[]): number {
    return Math.pow(value, 2);
  }

}

But when i try to use the template like this

it doesn't work I need to know why ?

<input type = "number" placeholder = "Enter number for which square is to be calculated" #value>
  <p>Squared Number is using pipe Transform  {{value | square}} </p>

Answer 1

I guess what you want is

<p>Squared Number is using pipe Transform  {{value.value | square}} </p>

value alone refers to the HTMLInputElement