1{{ number | number : '1.2-2'}}
2

1//{{ value_expression | number [ : digitsInfo [ : locale ] ] }}
2
3//Assume someNumber = 12.221
4	<!--output '12'-->
5	<p>{{ someNumber | number : '1.0-0'}}</p>
6
7//The output here is '12' because we cut the decimals off
8//with the number pipe
9
10//More examples from Angular:
11
12	//Assume:
13    //pi: number = 3.14;
14  	//e: number = 2.718281828459045;
15
16	<!--output '2.718'-->
17    <p>e (no formatting): {{e | number}}</p>
18
19    <!--output '002.71828'-->
20    <p>e (3.1-5): {{e | number:'3.1-5'}}</p>
21
22    <!--output '0,002.71828'-->
23    <p>e (4.5-5): {{e | number:'4.5-5'}}</p>
24
25    <!--output '0 002,71828'-->
26    <p>e (french): {{e | number:'4.5-5':'fr'}}</p>
27
28    <!--output '3.14'-->
29    <p>pi (no formatting): {{pi | number}}</p>
30
31    <!--output '003.14'-->
32    <p>pi (3.1-5): {{pi | number:'3.1-5'}}</p>
33
34    <!--output '003.14000'-->
35    <p>pi (3.5-5): {{pi | number:'3.5-5'}}</p>
36
37    <!--output '-3' / unlike '-2' by Math.round()-->
38    <p>-2.5 (1.0-0): {{-2.5 | number:'1.0-0'}}</p>
39
40//More information here: https://angular.io/api/common/DecimalPipe

1<input [ngModel]="item.value | useMyPipeToFormatThatValue" 
2      (ngModelChange)="item.value=$event" name="inputField" type="text" />
3