Calculate column quantity total in angular

Question

I have an array of objects that contain a quantity field. I'm looking to total one field from the array on a review screen on a table.

I have an array of administrations populated with object fields and the one I'm looking to calculate is the 'quantity field'.

<tr class="primary" *ngFor="let medication of sachets">
    <td>{{medication.administration.quantity}}</td>
    <td>
        {{medication.medicationName}}
        <p class="instructions">{{medication.additionalInstructions}}</p>
    </td>
</tr>

Within the table, I am calculating the length of entries using angulars .length

I'm looking to calculate a total for the array of quantities.

Answer 1

Found a solution to filter and add the values. I used the .map function to create an array of quantity values, and using .reduce, add them together to give the desired total.

totalFunction() {
  const initialValue = 0;
  this.totalQuantity = this.administered.map
  (item => item.administration.quantity).reduce(
  (previousValue, currentValue) => previousValue + currentValue,
  initialValue);
  console.log(this.totalQuantity);
}