What dose the question mark do in a return variable?

[shaunmac]

Please forgive my ignorance, or if this is a stupid question.
In the following component the final return line is return data?.posts.
What does the question mark do? Append post if not empty?
And trying to google a question mark is not helping.

Also how do you add generalSettings to the return?

The following didn't work

return data?.posts.generalSettings
return data?{.posts,.generalSettings}

Component

export async function getAllPostsForHome(preview) {
  const data = await fetchAPI(
    `
    query AllPosts {
      posts(first: 20, where: {orderby: {field: DATE, order: DESC}}) {
        edges {
          node {
            title
            excerpt
            slug
            date
            featuredImage {
              node {
                sourceUrl
              }
            }
            author {
              node {
                name
                firstName
                lastName
                avatar {
                  url
                }
              }
            }
          }
        }
      }
      generalSettings {
        title
        description
      }
    }

  `,
    {
      variables: {
        onlyEnabled: !preview,
        preview,
      },
    }
  )

  return data?.posts
}

[omar-dulaimi]

I think this is what you want:
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Optional_chaining

[shaunmac]

Hey @omar-dulaimi, thank you for the link.
I think I get it, so you can just chain properties together and if they don't exist its stored as undefined.

So in the example above I should use:
return data?.posts?.generalSettings