Why is an empty array returned on filter().includes()? [duplicate]

Question

I can't figure out why my filter/includes is returning an empty array.

I have an array that works as the filter I set.

For example, filterLevels and the array is [100,200] This console.logs out correctly to an array with these vals (integers). The levels array in the data set are also integers and I've double checked. I've console logged out my data set and everything looks good there too.

I'd expect back every overlapping item in both my filtering array and data set. So for the above example I expect the first 3 items from the data set (where there is any match of levels).

console output is an empty array? I must be missing something small?

const filterLevels = [100,200]
const learningMapsData = [{
    "name": "Enterprise Networking",
    "Technology": "Networking",
    "levels": [100, 200]
  },
  {
    "name": "Develop",
    "Technology": "Software",
    "levels": [100, 200, 300]
  },
  {
    "name": "Test it out",
    "Technology": "Testing",
    "levels": [200, 300]
  },
  {
    "name": "Rout it",
    "Technology": "Routing",
    "levels": [300, 400]
  }
]

const intersection = learningMapsData.filter(element => filterLevels.includes(element.levels));
console.log("intersection::::::::::::", intersection);

Answer 1

You may go like this:

const intersection = learningMapsData.filter(element => element.levels.find(level => filterLevels.includes(level)));