angular2 Create a variable inside a constructor

Question

I want to create a variable inside a constructor (or function). I don't wanna created in the entire class. Is that possible?

This is my code

import { Component, OnInit } from '@angular/core';
import { FormGroup, FormBuilder, Validators } from '@angular/forms';
import { CustomValidators } from 'ng2-validation';
import { TranslatorService } from '../../../../core/translator/translator.service';
import { CarBrandService } from '../car-brand.service';
import { Response } from '../../../../shared/models/response';
import { SessionService } from '../../../../shared/services/session/session.service';
import { ServerService } from '../../../../shared/services/server/server.service';
import { ToasterService, ToasterConfig } from 'angular2-toaster/angular2-toaster';
import { Router } from '@angular/router';
import { CarBrand } from '../car-brand';
import { SharedModule } from '../../../../shared/shared.module';
import { Table } from '../../../../shared/models/table';
import { TableRow } from '../../../../shared/models/table-row';
import { TableAction } from '../../../../shared/models/table-action';
import { ListTableComponent } from '../../../../shared/components/list-table/list-table.component';

@Component({
  selector: 'car-brand-index',
  templateUrl: './index.component.html',
  styleUrls: ['./index.component.scss'],
  providers: [CarBrandService, Response, SessionService, ServerService,             ListTableComponent, TableAction, Table, TableRow]
})
export class CarBrandIndexComponent implements OnInit {
  error : String;
  total : number;
  items : Array<CarBrand>;
  table : Table;
  constructor(public translator: TranslatorService, private mainService : CarBrandService, public sessionService : SessionService, public response : Response, private toasterService: ToasterService, private router: Router) {

    var action : TableAction;
    action.value = "/view/";
    action.type = "link";
    this.table.actions.push(action);
    var action : TableAction;
    action.value = "/edit/";
    action.type = "link";
    this.table.actions.push(action);
    this.table.columns = ["MODULES.COMMON.LOGO", "MODULES.COMMON.NAME", "MODULES.COMMON.ACTIONS"];    
    this.getItems(1,10);
  }

  getItems(pageNumber : number, pageSize : number){
//Do something
            });        
        }
        else
          this.error = result.code;
    });
  }
  ngOnInit() {
       }
}

This is TableAction

export class TableAction {
    type : String;
    value : String;
    name : String;
    icon : String;
}

But in the following line var action : TableAction; It tells me that action is undefined. Is there a way to fix this without havong to declare the var below the class?

its undefined because you never initialize the value I think. So try let action: TableAction = new TableAction(); — Zyga
– Zyga, Commented Feb 13, 2017 at 11:28

karina · Accepted Answer · 2017-02-13 11:47:52Z

2

var action : TableAction; You just tell about 'action' type. Now if u trying assign to action something like {a: 1, b: 2} -- you will see an error.

but if u write var action : TableAction = new TableAction() -- you will have an instance in your scope (contructor/function) as you wanted and also define a type for the variable 'action'.

Advice: use let instead of var

let action = new TableAction();

A behavior of variables which were defined with the keyword 'let' are more predictable.

constructor() {
  let action1 = new TableAction("/view/", "link");
  this.table.actions.push(action1);

  let action2 = new TableAction("/edit/", "link");
  this.table.actions.push(action2);
  // ...
}

export class TableAction {
  type : String;
  value : String;
  name : String;
  icon: String;

  constructor(value, type) { 
    this.value = value;
    this.type = type;
  }
}

edited Feb 13, 2017 at 11:47

answered Feb 13, 2017 at 11:41

karina

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Comments

Suraj Rao · Accepted Answer · 2017-02-13 11:32:26Z

1

var action : TableAction

is a declaration.

var action : TableAction=new TableAction();

or

var action : TableAction = {};

is a definition. You are trying to set object properties of action which is not defined

answered Feb 13, 2017 at 11:32

Suraj Rao

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