Merge and remove duplicates from multiple arrays

My function takes an array of arrays and returns the merged array without duplicates

function mergeArrayOfPrimitives<T>(
  primitiveArraysTobeMerged: Array<Array<T>>
): Array<T> {
  const merged: Array<T> = [];
  primitiveArraysTobeMerged.forEach((primitiveArray: Array<T>) =>
    [...merged].concat([...primitiveArray])
  );
  return [...new Set([...merged])];
}

But when I test it on typescript playground with below inputs, it returns [] instead of ['CORE - AGILE']

console.log(mergeArrayOfPrimitives([[], ['CORE - AGILE']])); ==> [LOG]: []