How to filter array based on nested array data?

December 5, 2022

I have an array with a few objects:

const x = [
  {label: 'a', data: [0,0]},
  {label: 'b', data: [0,0]},
  {label: 'c', data: [0,1]}
  {label: 'd', data: [0,1]},
]

I want to filter out the objects where the data values are equal to 0 and end up with:

const x = [
  {label: 'c', data: [0,1]}
  {label: 'd', data: [0,1]},
]

I tried:

const result = x.filter((x) => {
    return x.data.filter((value) => value > 0);
});

expecting the .filter() to only return objects where the value would be higher than 0, but this is not working as expected.

>Solution :

Your inner .filter() method always returns an array, which is considered a truthy value. So the outer .filter() keeps all objects. Instead, you can use .some() to return true if any of the values in the data array are > 0 to keep the object in the resulting array:

const x = [ {label: 'a', data: [0,0]}, {label: 'b', data: [0,0]}, {label: 'c', data: [0,1]}, {label: 'd', data: [0,1]}, ];

const result = x.filter((x) => {
  return x.data.some((value) => value > 0);
});
console.log(result);