modifying an object using ... in JavaScript

Question

I have an object called added that looks like this:

{
  title: "test1",
  startDate: "Mon Apr 15 2019 10:30:00 GMT-0500 (Central Daylight Time)",
  endDate: "Mon Apr 15 2019 11:00:00 GMT-0500 (Central Daylight Time)",
  allDay: false
}

I was trying edit the startDate and endDate field of this object by doing:

added = {
  ...added,
  {added.startDate: "111", added.endDate: "222"}       
}

But this gives me an error that says

unexpected token, expected ,

What is the right way of doing this?

Possible duplicate of Using spread operator to update an object value — Dan O
– Dan O, Commented Apr 14, 2019 at 22:41

CertainPerformance · Accepted Answer · 2019-04-14 22:35:43Z

5

When reassigning added as a new object literal, everything inside the {}s needs to be key-value pairs, or it needs to spread (with ...) an object with key-value pairs into the new object. You can't put a plain object into an object literal (unless you spread it), because an object is a value, not a key-value pair.

Change to:

added = {
  ...added,
  startDate: "111",
  endDate: "222"
}

You could also do

added = {
  ...added,
  ...{
    startDate: "111",
    endDate: "222"
  }
}

which would be valid syntax (but silly do to - easier to just list the new properties in the outer object literal).

answered Apr 14, 2019 at 22:35

CertainPerformance

373k55 gold badges354 silver badges359 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

modifying an object using ... in JavaScript

1 Answer 1

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related