splitSpaceDelimitedString function

List<String> splitSpaceDelimitedString(String string)

Returns a List of space-delimited tokens efficiently split from the specified string.

Useful for splitting CSS className strings into class tokens, or data-test-id values into individual test IDs.

Handles leading and trailing spaces, as well as token separated by multiple spaces.

Example:

splitSpaceDelimitedString('   foo bar     baz') // ['foo', 'bar', 'baz']

Implementation

List<String> splitSpaceDelimitedString(String string) {
  const int SPACE = 32; // ' '.codeUnits.first;

  List<String> strings = [];
  int start = 0;

  while (start != string.length) {
    while (string.codeUnitAt(start) == SPACE) {
      start++;
      if (start == string.length) {
        return strings;
      }
    }

    int end = start;
    while (string.codeUnitAt(end) != SPACE) {
      end++;
      if (end == string.length) {
        strings.add(string.substring(start, end));
        return strings;
      }
    }

    strings.add(string.substring(start, end));

    start = end;
  }

  return strings;
}