cli: modify split behaviour

Now it splits 'str' till limit is bound or no more separators
left in 'str' if leaveEmpty is true then multiple separators
in sequence are written in the resulting array as one empty
string (''), else they are skipped and doesn't get counted to limit

PR-URL: #132
Reviewed-By: Mykola Bilochub <nbelochub@gmail.com>
Reviewed-By: Alexey Orlenko <eaglexrlnk@gmail.com>

tools/cli.js

@@ -101,24 +101,37 @@ commandProcessor.exit = () => {
   process.exit();
 };
 
+// str - inputs string
+// separator - string to use as a separator
+// limit - resulting length of output array - 1 (last one is what's left),
+//         if !limit === true => means no limit and split till no more
+//         separators found
+// leaveEmpty - if true multiple separators in sequence will be added as empty
+//              empty string, else they are skipped
+//
+// returns an array of strings
+//
+// the behaviour is as follows:
+//  splits 'str' till limit is bound or no more separators left in 'str'
+//  if leaveEmpty is true then multiple separators in sequence are written in
+//  resulting array as one empty string (''), else they are skipped
+//  and doesn't get counted to limit
 function _split(str, separator, limit, leaveEmpty) {
-  const shouldTrim = (start, split) => !leaveEmpty && start === split;
+  const isLastEmpty = arr => !arr[arr.length - 1];
 
   const result = [];
   let start = 0;
 
   // eslint-disable-next-line no-unmodified-loop-condition
-  for (let i = 0; !limit || i < limit; i++) {
+  while (!limit || limit - result.length > 0) {
     const split = str.indexOf(separator, start);
     if (split === -1) break;
-    if (!shouldTrim(start, split)) {
+    if (start !== split || leaveEmpty && !isLastEmpty(result)) {
       result.push(str.slice(start, split));
-    } else  {
-      i--;
     }
     start = split + separator.length;
   }
-  if (!shouldTrim(start, str.length)) {
+  if (start !== str.length || leaveEmpty && !isLastEmpty(result)) {
     result.push(str.slice(start));
   }
   return result;