wc.js

import { program } from "commander";
import { promises as fs } from "node:fs";

//configuring 
program
  .name("wc")
  .description("Print newline, word, and byte counts for each file")
  .option("-l, --lines", "Print the newline counts")
  .option("-w, --words", "Print the word counts")
  .option("-c, --bytes", "Print the byte counts")
  .argument("<files...>", "File paths to process")
//Interpret the program
  program.parse()
const options = program.opts()
const files = program.args //Interpreting parsed data


//helper function to calculate all counts 
async function getCounts(file){
  const content = await fs.readFile(file, "utf-8");
  const lineCount = content.split("\n").length -1;//split("\n") returns one more element than the actual number so length-1,
  const wordCount = content.trim().split(/\s+/).length;
  const byteCount = Buffer.byteLength(content, "utf-8"); //Calculate how many bytes the string uses in UTF-8 (important because some characters use more than 1 byte)
  return { lineCount, wordCount, byteCount };
}
//initiating totals
let totalLines = 0;
let totalWords = 0;
let totalBytes = 0;

for (const file of files) {
  const { lineCount, wordCount, byteCount } = await getCounts(file);

  totalLines += lineCount;
  totalWords += wordCount;
  totalBytes += byteCount;

let output = "";
  if (options.lines) output += `${lineCount} `;
  if (options.words) output += `${wordCount} `;
  if (options.bytes) output += `${byteCount} `;
  if (!options.lines && !options.words && !options.bytes) {
    output += `${lineCount} ${wordCount} ${byteCount} `;
  }
  output += file;
  console.log(output);
}
  
  
  //Print totals if multiple files
if (files.length > 1) {
  let totalOutput = "";
  if (options.lines) totalOutput += `${totalLines} `;
  if (options.words) totalOutput += `${totalWords} `;
  if (options.bytes) totalOutput += `${totalBytes} `;
  if (!options.lines && !options.words && !options.bytes) {
    totalOutput += `${totalLines} ${totalWords} ${totalBytes} `;
  }
  totalOutput += "total";
  console.log(totalOutput);
}