export const assign = Object.assign
copy values from one or more sources to a target see: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/assign
export const assign = Object.assign
test if an object is an array
export const isArray = Array.isArray
test if is a string
export const isString = x => typeof x === "string"
test if is a function
export const isFn = x => typeof x === "function"
test if is defined
export const isDef = x => typeof x !== "undefined"
get last element from an array
export const last = a => a[a.length - 1]
take the next element of stack without remove it
export const peek = last