safe-object.js

// safe objects won't throw when trying to get a
// property which doesn't exist.

const safe = value => new Proxy({
  extract() {
    return value
  }
}, {
  get(obj, key) {
    return key === 'extract'
      ? obj[key] 
      : safe(
          value !== undefined && value !== null
            ?  value[key]
            : value
        )
  }
})

const user = {
  name: 'Paul',
  location: {
    city: 'Paris'
  },
  friends: [
    {
      name: 'Patrick'
    }
  ]
}


console.log(safe(user).name.extract())
// => Paul
console.log(safe(user).friends[0].name.length.extract())
// => 7
console.log(safe(user).friends[3].name.length.extract())
// => undefined