This is not a method in lodash that does a good job of supporting a case to use the full lodash library these days as the native array split method is well supported, and the lodash split method does not really bring anything more to the table compared to other lodash methods where that is the case at least.
For a basic example of the _.split method in lodash say you have a serialized string of css property and value pairs and you want an array of pairs rather than just a string. The _.split method can be used to break the string into such an array by using the semicolon as a separator. Just pass the string as the first argument, and then the semicolon as the second argument.
The resulting array that will be returned is then an array of substrings of property and value pairs for css rules.
The one difference is that you will want to end the chain by calling value so that a value is returned.
A regular expression can be used as the separator, rather than a static string. This is useful if I want some kind of pattern to be used as a way to break the string down rather than a static fixed string value.