add wc tool with line, word, and byte counts in NodeJS

Author: Pezhman-Azizi

implement-shell-tools/wc/wc.js

@@ -0,0 +1,87 @@
+#!/usr/bin/env node
+
+const fs = require("fs");
+const path = require("path");
+
+// -------- argument parsing --------
+const args = process.argv.slice(2);
+
+let countLines = false;
+let countWords = false;
+let countBytes = false;
+let files = [];
+
+// flags can appear in any order
+for (const arg of args) {
+  if (arg === "-l") countLines = true;
+  else if (arg === "-w") countWords = true;
+  else if (arg === "-c") countBytes = true;
+  else files.push(arg);
+}
+
+if (files.length === 0) {
+  console.error("Usage: wc [-l] [-w] [-c] <file> [file...]");
+  process.exit(1);
+}
+
+// If no flags → behave like plain `wc`
+if (!countLines && !countWords && !countBytes) {
+  countLines = true;
+  countWords = true;
+  countBytes = true;
+}
+
+// -------- helpers --------
+function countFile(filePath) {
+  let content;
+  let buffer;
+
+  try {
+    buffer = fs.readFileSync(filePath);
+    content = buffer.toString("utf8");
+  } catch (err) {
+    console.error(`wc.js: ${filePath}: ${err.message}`);
+    return null;
+  }
+
+  const lines = content.split("\n").length - 1;
+  const words = content.trim() === ""
+    ? 0
+    : content.trim().split(/\s+/).length;
+  const bytes = buffer.length;
+
+  return { lines, words, bytes };
+}
+
+function formatOutput(counts, fileName) {
+  const parts = [];
+
+  if (countLines) parts.push(counts.lines.toString().padStart(7, " "));
+  if (countWords) parts.push(counts.words.toString().padStart(7, " "));
+  if (countBytes) parts.push(counts.bytes.toString().padStart(7, " "));
+
+  parts.push(" " + fileName);
+  return parts.join("");
+}
+
+// -------- main --------
+let total = { lines: 0, words: 0, bytes: 0 };
+let validFileCount = 0;
+
+for (const file of files) {
+  const counts = countFile(file);
+  if (!counts) continue;
+
+  validFileCount++;
+
+  total.lines += counts.lines;
+  total.words += counts.words;
+  total.bytes += counts.bytes;
+
+  process.stdout.write(formatOutput(counts, file) + "\n");
+}
+
+// Print total if multiple files
+if (validFileCount > 1) {
+  process.stdout.write(formatOutput(total, "total") + "\n");
+}