Function transformVariadicArgumentToArray

We want to provide methods which accept a variable single number of elements and arrays. The overloaded signature to achieve this is:

function doSomething(array: T[])
function doSomething(...varArgs: T[])
function doSomething(first: undefined | T | T[], ...rest: T[]) {
  //implementation
}

This wrapper methods makes it easy build an array from the input.

Returns

Array from the input or empty array if no input was given.