Angular 7, nested function using same variable

问题

I'm trying to run one function - "createThreeDates()" that can generate three different results (dates based on -90, -60, -45), using the same variable. After a user sets a date in the input field, that date variable is set and used in the function. The Generate 1 button calls the function. Everything works fine if I only needed one date (not three). FYI, this function uses the installed/import package "add-subtract-date."

There are NO ERRORS in my code, but the function returns the SAME date (fortyDaysDate) to all three input fields in the browser (?). -I don't know how this is possible when I have different ngModels.

Here is component.ts...

    import { Component, EventEmitter, Input, Output, OnInit } from '@angular/core';
    import { CalculatorService } from '../calculator.service';
    import { add, subtract } from 'add-subtract-date';
    import { NgForm, FormGroup } from '@angular/forms';


    @Component({
      selector: 'app-home',
      templateUrl: './home.component.html',
      styleUrls: ['./home.component.css']
    })
    export class HomeComponent implements OnInit {

      public fortyDaysDate: any;
      public sixtyDaysDate: any;
      public ninetyDaysDate: any;



      private _retireSet: Date;
      @Input() set retireSet(date: Date) {
        this._retireSet = new Date(date);
      }

    constructor(private calculatorService: CalculatorService) { 
      }

      ngOnInit() {
      }

    public createThreeDates(): void {
      let d: Date = this._retireSet;
      let ninetyDaysBack = subtract(d, 90, "days");
      this.ninetyDaysDate = ninetyDaysBack;
  console.log('90 is ' + this.ninetyDaysDate);

        let sixtyDaysBack = add(d, 30, "days");
        this.sixtyDaysDate = sixtyDaysBack;
        console.log('60 is ' + this.sixtyDaysDate);

         let fortyDaysBack = add(d, 15, "days");
         this.fortyDaysDate = fortyDaysBack;
         console.log('45 is ' + this.fortyDaysDate);

// the value of sixtyDaysDate changes to fortyDaysDate value here...
         console.log('60 is ' + this.sixtyDaysDate);

        }
    }

    }

Here is component.html...

 <div class="container">
    <form class="ret-form" #calcForm="ngForm" novalidate (ngSubmit)="onSubmit(calcForm)">

    <div class="form-group">
        <label for="retireSet">Set Date</label>
        <input type="datetime-local" id="retireSet" name="RetireCalculatorSetDate" value="retireSet" 
        ngModel #RetireCalculatorSetDate="ngModel" [(ngModel)]="retireSet" class="form-control" />
    </div>

    <div>
 <button type="button" class="btn btn-lg btn-outline-dark" (click)="createThreeDates()">Generate 1</button>      

    <div>
  <input type="text" name="RetireCalculatorDay90" value="ninetyDaysDate" ngModel #RetireCalculatorDay90="ngModel" 
  [(ngModel)]="ninetyDaysDate" class="form-control" />
    </div>

    <div>
  <input type="text" name="RetireCalculatorDay60" value="sixtyDaysDate" ngModel #RetireCalculatorDay60="ngModel" 
  [(ngModel)]="sixtyDaysDate" class="form-control" />
    </div>

  <input type="text" name="RetireCalculatorDay45" value="fortyDaysDate" ngModel #RetireCalculatorDay45="ngModel" 
[(ngModel)]="fortyDaysDate" class="form-control" />
    </div>


    </form>
    </div>

回答1:

This is more of a code review than an answer. Your syntax is not correct here.

Remove the curly braces inside the function.
Make sure the function "subtract" is not mutating the variable passed in. You may want to "clone" the variable "_retireSet" so that you're not mutating it inside this function.
Use "const" if you're not reassigning the variable. In this function you are so you need to use "let".
As @crashmstr noted change the function return type to void

Side note: Function name is confusing. "getAllDates" this is implying you're returning an object with dates. Instead change the name to prepareAllDates or createAllDates or something similar.

Remember that "Set" and "Get" implies "Setting a Variable" and "Getting a Variable" respectively.

** Update ** From your comment below it looks like you're having an issue with javascript itself.

Assign By Value

var batman = 7;
var superman = batman;   //assign-by-value
superman++;
console.log(batman);     //7
console.log(superman); //8

Assign By Reference

var flash = [8,8,8];
var quicksilver = flash;   //assign-by-reference
quicksilver.push(0);
console.log(flash);        //[8,8,8,0]
console.log(quicksilver); //[8,8,8,0]

For your specific issue:

var x = new Date()

var y = new Date(x)

x.setFullYear('2019');

x //Date 2019-11-01T13:59:56.083Z
y //Date 2018-11-01T13:59:56.083Z

回答2:

After the advice I got on this post, here is the code that worked (FYI) resolving the issues.

component.HTML...

  <div class="form-group">
                <label for="retireSet">Set Retirement Date</label>
                <input type="datetime-local" id="retireSet" name="RetireCalculatorSetDate" ngModel #RetireCalculatorSetDate="ngModel"
 [(ngModel)]="retireSet" [(ngModel)]="retireSet60" [(ngModel)]="retireSet45" 
                    class="form-control" /> <div>

           <div><button type="button" class="btn btn-light" (click)="createThreeDates()">Calculate Dates</button> </div> 

    <div>
                <input type="hidden" name="RetireCalculatorDay90" value="ninetyDaysDate" ngModel #RetireCalculatorDay90="ngModel"
                [(ngModel)]="ninetyDaysDate" class="form-control" />
                <p class="textNinety"> 90 day notice is due {{ ninetyDaysDate | date: "longDate" }}. </p>
            </div>

     <div>
                <input type="hidden" name="RetireCalculatorDay60" value="sixtyDaysDate" ngModel #RetireCalculatorDay60="ngModel"
                [(ngModel)]="sixtyDaysDate" class="form-control" />
                <p>  60 day notice is due {{ sixtyDaysDate | date: "longDate" }}. </p>
            </div>   


     <div>
                <input type="hidden" name="RetireCalculatorDay45" value="fortyDaysDate" ngModel #RetireCalculatorDay45="ngModel"
                [(ngModel)]="fortyDaysDate" class="form-control" />
                <p> 45 day notice is due {{ fortyDaysDate | date: "longDate" }}. </p>
            </div>

component.ts...

import { Component, EventEmitter, Input, Output, OnInit } from '@angular/core';
import { CalculatorService } from '../calculator.service';
import { add, subtract } from 'add-subtract-date';
import { NgForm, FormGroup } from '@angular/forms';


@Component({
  selector: 'app-home',
  templateUrl: './home.component.html',
  styleUrls: ['./home.component.css']
})
export class HomeComponent implements OnInit {

  public fortyDaysDate: any;
  public sixtyDaysDate: any;
  public ninetyDaysDate: any;
  public myRetDatePlus45: Date;
  public myRetDatePlus60: Date;
  public myRetDatePlus90: Date;

 private _retireSet: Date;
  @Input() set retireSet(date: Date) {
    this._retireSet = new Date(date);
    this.myRetDatePlus90 = this._retireSet;
  }

  private _retireSet60: Date;
  @Input() set retireSet60(date: Date) {
    this._retireSet60 = new Date(date);
    this.myRetDatePlus60 = this._retireSet60;
  }

  private _retireSet45: Date;
  @Input() set retireSet45(date: Date) {
    this._retireSet45 = new Date(date);
    this.myRetDatePlus45 = this._retireSet45;
  }


  constructor(private calculatorService: CalculatorService) { 
  }

  ngOnInit() {
  }



 public createThreeDates(): void { 
  let dNinety: Date = this.myRetDatePlus90;
  let ninetyDaysBack = subtract(dNinety, 90, "days");
  this.ninetyDaysDate = ninetyDaysBack;

 let dSixty: Date = this.myRetDatePlus60;
 let sixtyDaysBack = subtract(dSixty, 60, "days");
 this.sixtyDaysDate = sixtyDaysBack;
 console.log('60 is ' + this.sixtyDaysDate);

  let dForty: Date = this.myRetDatePlus45;
  let fortyDaysBack = subtract(dForty, 45, "days");
  this.fortyDaysDate = fortyDaysBack;
 }

来源：https://stackoverflow.com/questions/53050431/angular-7-nested-function-using-same-variable

标签

angular

angular7