How to read a file line by line in Dart

Question

This question is a continuation of a previous question. I wrote the following piece of code to determine if File.openRead() created a Stream that could be stre

Answer 1

Because none of the other answers suited my situation, here is another technique:

import 'dart:io';
import 'dart:convert';


void main()
{
    var file = File('/path/to/some/file.txt);
    var raf = file.openSync(mode: fileMode.read);

    String line;
    while ((line = readLine(raf)) != null)
    {
        print(line);
    }
  }

  String readLine(RandomAccessFile raf, {String lineDelimiter = '\n'}) {

    var line = '';
    int byte;
    var priorChar = '';

    var foundDelimiter = false;

    while ((byte = raf.readByteSync()) != -1) {
      var char = utf8.decode([byte]);

      if (isLineDelimiter(priorChar, char, lineDelimiter)) {
        foundDelimiter = true;
        break;
      }

      line += char;
      priorChar = char;
    }
    if (line.isEmpty && foundDelimiter == false) {
      line = null;
    }
    return line;
  }


  bool isLineDelimiter(String priorChar, String char, String lineDelimiter) {
    if (lineDelimiter.length == 1) {
      return char == lineDelimiter;
    } else {
      return priorChar + char == lineDelimiter;
    }
  }