Using replace values between two json objects with rxjs in angular

Question

I want to use Rxjs map() method to switch values between two json objects. Or if there are any better rxjs methods I am open to suggestions

For example if I have two json objects:

[{"firstname":"abc","lastname":"bcd"},{"firstname":"xyz","lastname":"zzz"}]

How do I for example switch the values of first name from both json objects in the array as well as the lastnames? I am very new to rxjs!

Thanks!

Does your `Observable` emit `{"firstname":"abc","lastname":"bcd"}`, then `{"firstname":"abc","lastname":"bcd"}`, or does it emit `[{"firstname":"abc","lastname":"bcd"},{"firstname":"xyz","lastname":"zzz"}]` all at once? — hugo, Aug 01 '19 at 13:57
what is the desire output? switch both the firstname and the lastname? — Bill Cheng, Aug 01 '19 at 14:12
... and what you have actually tried to achieve this. This is not a coding service ;) — AT82, Aug 02 '19 at 12:23

score 0 · Answer 1 · answered Aug 01 '19 at 14:31

In your example, swapping the entire objects will work:

let swapped = observable.pipe(map(([first, second]) => [second, first]));

In older versions of JS (and made a bit verbose on purpose):

function swapPair(arr) {
    var first = arr[0];
    var second = arr[1];
    return [second, first];
}

var swapped = observable.pipe(map(swapPair));

If you want a more generic way to swap properties -- I was about to write something, but really it's been done before:

Using replace values between two json objects with rxjs in angular

1 Answers1