Filter/de-duplicate repeated variables

Question

I am trying to add functionality into my JS script that de-duplicates the values returned. My original script here:

try{
var productList = dataLayer.basket.products.map(function(product) {
    return product.travelType;
});

return productList.join('|');
  }
catch(err){}

which returns values from an array like Bus|Bus|Train|Car|Bus

What I am trying to get to is an additional part of the script that would clean those values and de-duplicate them. For example the above script would only show "bus" once e.g. Bus|Train|Car

I have tried to do this using a filter but I am getting a null value being returned:

try{
var productList = dataLayer.basket.products.map(function(product) {
    return product.travelType;
});
  
var filteredArray = productList.filter(function(item, pos){
    return productList.indexOf(item)=== pos;
  });
  
return filteredArray.join('|');
  }
catch(err){}

Any guidance would be gratefully appreciated.

Thanks, M

You have a return statement but no context for it - is this all inside a function? — Mixolydian, Feb 07 '19 at 15:15
it would be helpful to see the entire function that is returning a null value. — Mixolydian, Feb 07 '19 at 16:32

score 1 · Answer 1 · answered Feb 07 '19 at 15:14

1

To filter duplicates in an array:

const array = ['toto', 'tata', 'tutu', 'toto'];
const filteredArray = [...new Set(array)];

console.log(filteredArray);

answered Feb 07 '19 at 15:14

Leo

741
6
14

score 0 · Answer 2 · answered Feb 07 '19 at 15:15

0

const remove_duplicates = (arr) => {
    let setArr = new Set(arr);
    let values = setArr.values();
    return Array.from(values);
}
const example = ['Bus', 'Bus', 'Car', 'Bike'];

console.log(remove_duplicates(example).join('|'));

answered Feb 07 '19 at 15:15

Nicolae Maties

2,476
1
16
26

peabrainiac · Answer 3 · 2019-02-07T15:37:15.387

0

I think the top answer in this question is just what you're searching for. Just apply that to your productList and it should get rid of all duplicate values.

Edit: oops, I just saw you were already doing exaclty that. But your code should work that way, I just tried it out in the console and it worked just as expected. The null values must be caused by some other part of your program.

edited Feb 07 '19 at 15:37

answered Feb 07 '19 at 15:16

peabrainiac

998
9
16

score 0 · Answer 4 · answered Feb 07 '19 at 15:18

Your code is fine as is, the error must be in your data or in another part of your code that you didn't post:

const dataLayer = {
  basket:{products:[
      {travelType:'a'},
      {travelType:'b'},
      {travelType:'c'},
      {travelType:'b'},
      {travelType:'c'},
      {travelType:'a'},

  ]}
}

var productList = dataLayer.basket.products.map(function(product) {
  return product.travelType;
});
  
var filteredArray = productList.filter(function(item, pos){
  return productList.indexOf(item)=== pos;
});
  
console.log(filteredArray.join('|'));

score 0 · Answer 5 · answered Feb 07 '19 at 15:26

0

Using modern javascript:

let arr = ['Bus', 'Bus', 'Train', 'Car', 'Bus'];
let filteredArr= [... new Set(arr)]; 
let result = filteredArr.join('|');

answered Feb 07 '19 at 15:26

Bassem Mamar

328
2
14

Filter/de-duplicate repeated variables

5 Answers5