Implement a function intersectionBy(arrays, iteratee) that computes the intersection of multiple arrays, returning only the unique values that are present in all arrays. The comparison should be based on a provided iteratee function.

The function should:

• Accept an array of arrays.
• Accept an iteratee function that transforms values for comparison.
• Return an array of unique values present in all arrays, using the iteratee to determine equality.

Example

intersectionBy([[2.1, 1.2], [2.3, 3.4]], Math.floor); // [2]
intersectionBy([[{x:1},{x:2}], [{x:2},{x:3}]], o => o.x); // [{x:2}]