Question

I'm newbie to the angular 2 / typescript. I'm working around around interfaces in typescript. I got the point as by using this we can check our type in compile or dev time itself. I had created a Interface ts file as like below with 2 properties and 1 function :

export interface EmpEnities{
empname : string;
deptname :string;
validation();
}

My Component :

import { Component } from '@angular/core';
import {EmpEnities} from './IEmloyee'

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
   styleUrls: ['./app.component.css']
})
export class AppComponent {
  title = 'app';
  Employees : EmpEnities[] = [
            {empname:'sreekanth',deptname:'xyz',validation(){return 'a'}},
            {empname:'sreekanth',deptname:'xyz',validation(){return false}},
            {empname:'sreekanth',deptname:'xyz',validation(){return true}}
            ]
}

I had perfectly got compile time error if any of the three members(2 properties + 1function) not used. Now my criteria is How can I make sure to get error, if my "Validation()" is not returning a bool value. If you observe in the array of object, the first validate() is returning string and remaining are returning boolean.

Can I specify the return type of the Function declared in Interface ?

Answer 1

尝试一下

export interface EmpEnities{
    empname : string;
    deptname :string;
    validation: () => boolean;
}

export class AppComponent {
    title = 'app';
    Employees : EmpEnities[] = [
                {empname:'sreekanth',deptname:'xyz',validation: () => {return 'a' === 'a'}},
                {empname:'sreekanth',deptname:'xyz',validation: () => {return false}},
                {empname:'sreekanth',deptname:'xyz',validation: () => true}
                ]
}

Function return type in interface

1 个答案: