This package can easily modify string to upper or lower case using lodash library. For example:

modifyString('abs', 'toUpper') === 'ABC'

If you don't pass the second argument it will modify your string to lower case by default.

But that is not all! This package also can modify your array. It can concat it or show differences between two arrays. For example:

modifyArray([1, 2, 3], { array: [1, 2], method: 'difference' }) => [3]