48-nesting-structure-comparison.js

// Complete the function/method (depending on the language) to return true/True
// when its argument is an array that has the same nesting structure as the first array.

// For example:

//  // should return true
// [ 1, 1, 1 ].sameStructureAs( [ 2, 2, 2 ] );
// [ 1, [ 1, 1 ] ].sameStructureAs( [ 2, [ 2, 2 ] ] );

//  // should return false
// [ 1, [ 1, 1 ] ].sameStructureAs( [ [ 2, 2 ], 2 ] );
// [ 1, [ 1, 1 ] ].sameStructureAs( [ [ 2 ], 2 ] );

// // should return true
// [ [ [ ], [ ] ] ].sameStructureAs( [ [ [ ], [ ] ] ] );

// // should return false
// [ [ [ ], [ ] ] ].sameStructureAs( [ [ 1, 1 ] ] );
// For your convenience, there is already a function 'isArray(o)' declared and
// defined that returns true if its argument is an array, false otherwise.

Array.prototype.sameStructureAs = function (other) {
  if (this.length !== other.length) {
    return false;
  }
  return this.reduce((acc, e, i) => {
    if (isArray(e) !== isArray(other[i])) {
      return false;
    }
    if (!isArray(e) && !isArray(other[i])) {
      return true;
    }
    return e.sameStructureAs(other[i]);
  }, true);
};