Assign each value to object

Question

I am taking data from my backend in this simple way

this.archiveService.getRooms(team).subscribe(
  res => {
   this.form = res;
    this.form.forEach(el => {
     el.reservation.slice(-6).match(/.{1,2}/g).join('/');
    });

  },
  error => {
    console.log(error);
  }
)

this.form is a Object I am getting reservation number from form then I want to slice everything that I don't want. ( Regex works fine ). Then I want to assign this prepared value into my this.form then I using *ngFor in table

How can I assign each value from forEach loop into this.form

Answer 1

As read in the documentation, the js slice method

Return A new array containing the extracted elements.

In fact, the slice methods does not modifiy the current element of the array

---

To solve your problem, you can either use the splice methods which works as the following :

The splice() method changes the contents of an array by removing or replacing existing elements and/or adding new elements in place. To access part of an array without modifying it, see slice().

this.form.forEach(el => {
     el.reservation.splice(-6).match(/.{1,2}/g).join('/');
    });

Or re-assign the value using the slice method

this.form.forEach(el => {
     el.reservation = el.reservation.slice(-6).match(/.{1,2}/g).join('/');
    });

Small example of usage

const myArr = [1,2,3,4,5,6,7,8,9,10]

const returnVal = myArr.slice(0,5)

console.log(`val return by slice : ${returnVal}`)
console.log(`current arr : ${myArr}`)

console.log('------------------')


const myArr2 = [1,2,3,4,5,6,7,8,9,10]

const returnVal2 = myArr2.splice(0,5)

console.log(`val return by splice : ${returnVal2}`)
console.log(`current arr : ${myArr2}`)

Answer 2

Propose of .foreach() doesn't serve what you want.

However, If you feel the life is quite ordinary and want to do some advance. Check is out Array.prototype.forEach()