feat(myWc): complete custom wc implementation with full options and formatting

Author: RahwaZeslusHaile

implement-shell-tools/wc/sample-files/myWc.js

@@ -0,0 +1,97 @@
+#!/usr/bin/env node
+const { program } = require("commander");
+const fs = require("fs");
+const path = require("path");
+
+function expandWildcard(pattern) {
+  const dir = path.dirname(pattern);
+  const base = path.basename(pattern);
+
+  if (!base.includes("*")) return [pattern];
+
+  let files;
+  try {
+    files = fs.readdirSync(dir);
+  } catch {
+    console.error(`wc: ${pattern}: No such directory`);
+    return [];
+  }
+
+  const regex = new RegExp("^" + base.replace(/\*/g, ".*") + "$");
+  return files
+    .filter(f => regex.test(f))
+    .map(f => path.join(dir, f));
+}
+
+function countLines(text) {
+  if (text === "") return 0;
+  const matches = text.match(/\n/g) || [];
+  return text.endsWith("\n") ? matches.length : matches.length + 1;
+}
+
+function countWords(text) {
+  return text.split(/\s+/).filter(Boolean).length;
+}
+
+function countChars(text) {
+  return Buffer.byteLength(text, "utf-8");
+}
+
+function wcFile(filename, options) {
+  let text;
+  try {
+    text = fs.readFileSync(filename, "utf-8");
+  } catch {
+    console.error(`wc: ${filename}: No such file`);
+    return null;
+  }
+
+  const lineCount = countLines(text);
+  const wordCount = countWords(text);
+  const charCount = countChars(text);
+
+  let output;
+  const paddingSize = 7;
+  if (options.lines && !options.words && !options.chars) output = `${lineCount} ${filename}`;
+  else if (options.words && !options.lines && !options.chars) output = `${wordCount} ${filename}`;
+  else if (options.chars && !options.lines && !options.words) output = `${charCount} ${filename}`;
+  else output = `${String(lineCount).padStart(paddingSize)} ${String(wordCount).padStart(paddingSize)} ${String(charCount).padStart(paddingSize)} ${filename}`;
+  console.log(output);
+
+  return { lines: lineCount, words: wordCount, chars: charCount };
+}
+
+program
+  .name("mywc")
+  .description("Custom implementation of wc")
+  .option("-l, --lines", "count lines")
+  .option("-w, --words", "count words")
+  .option("-c, --chars", "count characters")
+  .argument("<files...>", "files or wildcard patterns")
+  .action((patterns, options) => {
+    let allFiles = [];
+    patterns.forEach(p => allFiles = allFiles.concat(expandWildcard(p)));
+
+    let totalLines = 0, totalWords = 0, totalChars = 0;
+
+    allFiles.forEach(file => {
+      const result = wcFile(file, options);
+      if (result) {
+        totalLines += result.lines;
+        totalWords += result.words;
+        totalChars += result.chars;
+      }
+    });
+    const paddingSize = 7;
+    if (allFiles.length > 1) {
+      if (options.lines && !options.words && !options.chars) console.log(`${totalLines} total`);
+      else if (options.words && !options.lines && !options.chars) console.log(`${totalWords} total`);
+      else if (options.chars && !options.lines && !options.words) console.log(`${totalChars} total`);
+      else console.log(
+        `${String(totalLines).padStart(paddingSize)} ` +
+        `${String(totalWords).padStart(paddingSize)} ` +
+        `${String(totalChars).padStart(paddingSize)} total`);
+    }
+  });
+
+program.parse();