Some Deno code for reading a file a line by line asychronously

file.ts

// function that returns reads a file line by line asynchronously
export async function* readFileLineByLine(file: string) : AsyncGenerator<string> {
  const textDecoder = new TextDecoder();
  let stringBuffer: string = "";
  const fileHandle = await Deno.open(file);
  try {
    let intBuffer = new  Uint8Array(1000);
    let numberOfBytesRead = await fileHandle.read(intBuffer);
    while (numberOfBytesRead !== null) {
      const asString = textDecoder.decode(intBuffer);
      stringBuffer += asString;

      while (stringBuffer.includes("\n")) {
        const indexOfNewLine = stringBuffer.indexOf("\n");
        const newLine = stringBuffer.slice(0, indexOfNewLine);
        yield newLine;

        // replace the stringBuffer with the remaining string and keep processing
        stringBuffer = stringBuffer.slice(indexOfNewLine + 1);
      }
      intBuffer = new Uint8Array(1000);
      numberOfBytesRead = await fileHandle.read(intBuffer);
    }
  } finally {
    fileHandle.close();
  }
}