removing duplicates error, array[x] is not defined

I am trying to remove duplicates from data passed on from the Node. The function to fetch the data is:

getProducts(_) {
     const dev = "http://localhost:3008/api"
      fetch(dev) 
      .then(res => res.json())
      .then(data => {
       /* this.setState
        ({
          data: data.data
        })
      })*/
     this.removeDuplicates(data) 
      })
    }

My remove duplicates function is:

removeDuplicates(arr){ 
    let array = arr.data
  console.log(array)
    array.sort((a,b) => {return a.webservice - b.webservice}) 
  let length = array.length 
   for ( var i = 0; 
          i < length; 
          i++ ){
            let x = i+1
           console.log(array[x].webservice)
    /*  if (array[i].webservice == array[x].webservice){
        delete array[i]
      }*/
     // console.log(array)
      }
  }

When I console.log the data - it returns the array of object as expected. When I console.log the array[i].webservice - it returns the webservice But when I try to do the same for array[x].webservice (which is i+1) it returns array[x] is undefined fatal error but still console.logs the data.

Am I missing something here?