ARCcore.util is a small collection of JavaScript helper functions that are used by other libraries in the ARCcore package. You're very unlikely to need any of these trivial functions in your own code.
$ node
> const arccore = require('arccore');
undefined
> arccore.util
{ deepCopy: [Function],
clone: [Function],
dictionaryLength: [Function],
getEpochTime: [Function] }
>