function getLink(data: { [key: string]: any }) {
    // Only checks if the key is in the object
    if ('link' in data) {
        return data['link']
    }
    else return 'https://default.com'
}
console.log(getLink({}))
console.log(getLink({ link: 'https://google.com' }))
// Produces null or undefined
console.log(getLink({ link: null }))

function getLink(data: { link?: string, [key: string]: any }) {
    if (data.link) {
        return data.link
    }
    else return 'https://default.com'
}
console.log(getLink({ link: '' }))