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JavaScript

Marcus Thelin
Marcus Thelin
1,188 Points
Posted by Marcus Thelin
Marcus Thelin
1,188 Points

Where did we get the index value from?

For example when we do the 

toggleConfirmationAt = indexToChange => {
    this.setState({
      guests: this.state.guests.map((guest, index) => {
        if(index === indexToChange) {
          return {
            ...guest,
            isConfirmed: !guest.isConfirmed
          }
        }
        return guest;
      })
    })
  }

1 Answer

Steven Parker
Steven Parker
216,148 Points
Steven Parker
Steven Parker
216,148 Points

The map method supplies both the current item and it's index as arguments to the callback.

Marcus Thelin
Marcus Thelin
1,188 Points
Marcus Thelin
Marcus Thelin
1,188 Points

Thank you so much! I have totally missed that. Here's a reference to the ppl with the same questions: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map

Steven Parker
Steven Parker
216,148 Points
Steven Parker
Steven Parker
216,148 Points

Or you can click on the blue word "map" in my answer. :wink: