Wherefore art thou problem

JavaScript
7

I followed the suggestions above, but the code wouldn’t pass all the tests
Then I got the solution with the help from an other post in the forum
Then I created a pure function to make code less convoluted. Here comes just the pure function.

Spoiler 
 // a pure function
      let getProperties = (x) => {
        for (let prop in source) {
          //console.log('arr', arr[i][prop]);
          //  console.log('obj ', obj[prop]);
          if (x[prop] !== source[prop]) {
            return false
          }
        }
        return true
      }