truncate method

String truncate(int length, { String substitution = '', bool trimTrailingWhitespace = true, bool includeSubstitutionInLength = false, })

Returns a truncated version of the string.

Example:

final sentence = 'The quick brown fox jumps over the lazy dog';
final truncated = sentence.truncate(20); // 'The quick brown fox...'

The length is the truncated length of the string. The substitution is the substituting string of the truncated characters. If not null or empty it will be appended at the end of the truncated string. The trimTrailingWhitespace is whether or not to trim the spaces of the truncated string before appending the ending string. The includeSubstitutionInLength is whether or not that the length of the substitution string will be included with the intended truncated length.

Implementation

String truncate(
  int length, {
  String substitution = '',
  bool trimTrailingWhitespace = true,
  bool includeSubstitutionInLength = false,
}) {
  if (this.length <= length) {
    return this;
  }

  // calculate the final truncate length where whether or not to include the length of substitution string
  final truncatedLength = includeSubstitutionInLength
      ? (length - substitution.characters.length)
      : length;
  final truncated = this.characters.take(truncatedLength).toString();

  // finally trim the trailing white space if needed
  return (trimTrailingWhitespace ? truncated.trimRight() : truncated) +
      substitution;
}