[angular] Setting values of input fields with Angular 6

As an alternate you can use reactive forms. Here is an example: https://stackblitz.com/edit/angular-pqb2xx

Template

<form [formGroup]="mainForm" ng-submit="submitForm()">
  Global Price: <input type="number" formControlName="globalPrice">
  <button type="button" [disabled]="mainForm.get('globalPrice').value === null" (click)="applyPriceToAll()">Apply to all</button>
  <table border formArrayName="orderLines">
  <ng-container *ngFor="let orderLine of orderLines let i=index" [formGroupName]="i">
    <tr>
       <td>{{orderLine.time | date}}</td>
       <td>{{orderLine.quantity}}</td>
       <td><input formControlName="price" type="number"></td>
    </tr>
</ng-container>
  </table>
</form>

Component

import { Component } from '@angular/core';
import { FormGroup, FormControl, FormArray } from '@angular/forms';

@Component({
  selector: 'my-app',
  templateUrl: './app.component.html',
  styleUrls: [ './app.component.css' ]
})
export class AppComponent  {
  name = 'Angular 6';
  mainForm: FormGroup;
  orderLines = [
    {price: 10, time: new Date(), quantity: 2},
    {price: 20, time: new Date(), quantity: 3},
    {price: 30, time: new Date(), quantity: 3},
    {price: 40, time: new Date(), quantity: 5}
    ]
  constructor() {
    this.mainForm = this.getForm();
  }

  getForm(): FormGroup {
    return new FormGroup({
      globalPrice: new FormControl(),
      orderLines: new FormArray(this.orderLines.map(this.getFormGroupForLine))
    })
  }

  getFormGroupForLine(orderLine: any): FormGroup {
    return new FormGroup({
      price: new FormControl(orderLine.price)
    })
  }

  applyPriceToAll() {
    const formLines = this.mainForm.get('orderLines') as FormArray;
    const globalPrice = this.mainForm.get('globalPrice').value;
    formLines.controls.forEach(control => control.get('price').setValue(globalPrice));
    // optionally recheck value and validity without emit event.
  }

  submitForm() {

  }
}