function readFile(path, charset) {
  throw new Error("Function not implemented.");
}

function readTextFileIfExists(path) {
  return new Promise((resolve, reject) => {
    if (!path) {
      reject(new Error("No file path provided"));
      return;
    }

    readFile(path, "utf8")
      .then(data => {
        if (data.length === 0) {
          reject(new Error("File is empty")); // explicit failure
        } else {
          resolve(data); // successful read
        }
      })
      .catch(err => reject(err)); // I/O error
  });
}

readTextFileIfExists("data.txt")
  .then(text => console.log("File contents:", text))
  .catch(err => console.error("I/O error:", err.message));

try {
  const text = await readTextFileIfExists("data.txt");
  console.log("File contents:", text);
} catch (err) {
  console.error("I/O error:", err.message);
}

const files = ["file1.txt", "file2.txt", "file3.txt"];

for (const file of files) {
  try {
    const text = await readTextFileIfExists(file);
    console.log("File contents:", text);
  } catch (err) {
    console.error("I/O error:", err.message);
    continue;
  }
}

const otherFiles = ["does_not_exist.txt", "file2.txt", "file3.txt"];

const failContents = await Promise.all(
  otherFiles.map(readTextFileIfExists)
);
try {
    failContents.forEach((text, i) => {
      console.log("File contents:", text);
    });
} catch (err) {
    console.error("I/O error:", err.message);
}

const successContents = await Promise.allSettled(
  files.map(readTextFileIfExists)
);
successContents.forEach((result, i) => {
  if (result.status === "fulfilled") {
      console.log("File contents:", result.value);
  } else if (result.status === "rejected") {
      console.error("I/O error:", result.reason);
  }
});